Hello folks,
I have been privileged to see why some have gone down the road of conversion, its safer when you see the end result of a cheap and questionable build, the one I saw was a hack crank job that a goober weld was used in place of mallory metal to balance,it came loose and tore up / cracked the engine.
So instead of realizing it was a poor choice and doing a stand up build, they have done the safe move of putting in a warrantied vette motor???? Sound familiar. Just wish they would quit minimizing the 351 Cleveland
!
I have a 351 that I lost due to a valve coming off the stem, Great running engine for 38yrs. wow!
I have on a stand the same engine with an approx 620hp/carb and pump gas. I have no worry's if this engine will run well as I have many builds that I own that are running well 25 yr after the build.
The costs are a fraction of a crate engine but require a real commitment in time and knowledge.
The best parts are always used and payoff over time.
We have a treasure in this site and George for help and incite to support our efforts on on engine assembly.
Got to agree George is a treasure, I’ve been reading and re-reading the main how tos on here in combination with a lot of other Cleveland literature, and feel I’ve learned quite a bit more here than elsewhere.
So looking at the various pop ups available from Ross via Summit, looks like the w80552 and w80662 are my options both are -12cc which assuming a 4.030 overbore and no/minor skimming of the heads will give me ~10.5 static compression.
Here in the UK I can get 98/99 RON fuel from most petrol stations at a modest increase in cost, would I be correct in assuming that pushing the static ratio up and switching to higher octane gas would be preferable to further mitigate detonation issues given the open chambers on the 73 heads?
What sort of cam would be best to produce a high good streetable/occasional track day car looking at this scenario, something closer to the original Boss 351 grinds?
I’m not stuck on either solid or hydraulics either and would happily use whatever gives me a nice durable engine with serious punch.
So looking at the various pop ups available from Ross via Summit, looks like the w80552 and w80662 are my options both are -12cc which assuming a 4.030 overbore and no/minor skimming of the heads will give me ~10.5 static compression.
Here in the UK I can get 98/99 RON fuel from most petrol stations at a modest increase in cost, would I be correct in assuming that pushing the static ratio up and switching to higher octane gas would be preferable to further mitigate detonation issues given the open chambers on the 73 heads?
What sort of cam would be best to produce a high good streetable/occasional track day car looking at this scenario, something closer to the original Boss 351 grinds?
I’m not stuck on either solid or hydraulics either and would happily use whatever gives me a nice durable engine with serious punch.
The cylinder walls are too thin for anything greater than about 8.0:1 dynamic compression; i.e. fuel compatible with 91 octane pump gas (US & Canada) or 95 octane pump gas (Europe & Australia). An engine operating at 8.0:1 dynamic compression on 91 octane fuel, operated at wide open throttle is pushing the limits of the cylinder walls. So build the engine based on that limitation, no matter how high the octane of the pump gas which is available to you.
The amount of static compression the engine can use is dependent upon when the intake valve closes. A "bigger" cam can usually use more static compression. An engine can use about 11.0:1 static if the intake valve closes at 76 degrees ABDC.
Also be aware that raising compression is a situation of diminishing returns. Less horsepower is gained going from 10:1 to 11:1, than was gained going from 9:1 to 10:1. This is because the engine has to work harder to compress the fuel/air higher.
Finally, in my experience, open chamber heads are no more prone to detonation than quench heads.
Technically a solid roller tappet cam will make the biggest horsepower, but I'm a bit reluctant to recommend it. There are no rev-kits available for the 351C, and without a rev-kit the roller tappets take quite a beating due to the lash clearance. I can explain what I would do to operate a solid tappet roller cam ... if you wish. But the hydraulic roller tappet cam is a better bet for engine longevity because there is no lash clearance. A Cleveland for the street needs lots of lift but conservative duration to keep the overlap at or less than 60 degrees.
Here's what I consider the biggest "street cam"
(i.e. the valve events bump up against all of my valve event limits)
286°/290° duration at 0.006
232°/236° duration at 0.050 (approximately)
Lift will be limited by the valve spring.
The spring I've been recommending has a max lift of 0.630 inch.
114° LSA, 60° overlap
index the cam +1° (113° ICL)
This cam can use 10.8:1 static compression
That's a pretty bitchen cam. Too big for me at my age.
The amount of static compression the engine can use is dependent upon when the intake valve closes. A "bigger" cam can usually use more static compression. An engine can use about 11.0:1 static if the intake valve closes at 76 degrees ABDC.
Also be aware that raising compression is a situation of diminishing returns. Less horsepower is gained going from 10:1 to 11:1, than was gained going from 9:1 to 10:1. This is because the engine has to work harder to compress the fuel/air higher.
Finally, in my experience, open chamber heads are no more prone to detonation than quench heads.
Technically a solid roller tappet cam will make the biggest horsepower, but I'm a bit reluctant to recommend it. There are no rev-kits available for the 351C, and without a rev-kit the roller tappets take quite a beating due to the lash clearance. I can explain what I would do to operate a solid tappet roller cam ... if you wish. But the hydraulic roller tappet cam is a better bet for engine longevity because there is no lash clearance. A Cleveland for the street needs lots of lift but conservative duration to keep the overlap at or less than 60 degrees.
Here's what I consider the biggest "street cam"
(i.e. the valve events bump up against all of my valve event limits)
286°/290° duration at 0.006
232°/236° duration at 0.050 (approximately)
Lift will be limited by the valve spring.
The spring I've been recommending has a max lift of 0.630 inch.
114° LSA, 60° overlap
index the cam +1° (113° ICL)
This cam can use 10.8:1 static compression
That's a pretty bitchen cam. Too big for me at my age.
I like the sound of that bitchen cam very much, thanks for info George.
I’ll build with 91octane/95ron in mind as you suggest, last thing I want is blow holes in the cylinders.
And from there probably land somewhere in the 10.5 range static compression wise.
I’m thinking hydraulic roller at your suggestion there and I’ll take a look at my options with that in mind.
I did have a good look around the web for a rev kit, however despite many hints and allegations on various old forums I couldn’t find one, looks like the occasional old one ends up on ebay but nothing to rely on.
Now, that being said I think I’d love to hear how you would use the solid roller setup if only for educational purposes, as one of the very best things about your posting is the detailed reasoning behind the decisions you’d make. It really helps to illuminate so many of the pitfalls around how these old hunks of iron make real power without falling apart dramatically when doing so, and what compromises might be necessary to get there.
I’ll build with 91octane/95ron in mind as you suggest, last thing I want is blow holes in the cylinders.
And from there probably land somewhere in the 10.5 range static compression wise.
I’m thinking hydraulic roller at your suggestion there and I’ll take a look at my options with that in mind.
I did have a good look around the web for a rev kit, however despite many hints and allegations on various old forums I couldn’t find one, looks like the occasional old one ends up on ebay but nothing to rely on.
Now, that being said I think I’d love to hear how you would use the solid roller setup if only for educational purposes, as one of the very best things about your posting is the detailed reasoning behind the decisions you’d make. It really helps to illuminate so many of the pitfalls around how these old hunks of iron make real power without falling apart dramatically when doing so, and what compromises might be necessary to get there.
John, in autocrossing (also known as parking-lot racing), I got a backfire on the starting grid with a friend's Pantera that wasn't sufficiently warmed up. The 351-C had been rebuilt with 11:1 c.r, bored 0.030" over, big solid lifter cam & Holley carb, and needed 102 octane fuel to run without detonation. Immediately after the little backfire, water was seen running out one exhaust pipe. A teardown showed a piece of cylinder wall about 1" x 1" had cracked and blown clear into the water jacket. The retrieved piece showed a cylinder wall thickness of only 0.050"! For performance use, cylinder walls need at least 0.150" and more is better! Chev guys like to see 0.200"- no 351-C ever had such thick walls when new!
Lesson #1 learned: do NOT bore a 351-C AT ALL unless you first run a cylinder wall thickness check. This block had a shifted casting core on that cylinder.
Lesson #2: As you found out, stock valves are made in two pieces and WILL separate at the head-to-stem weld if overstressed. And 'overstressing' is ridiculously easy on a completely stock 351-C. Air-cooled VW valves are made the same way. Use ONLY one-piece valves which require single-groove keepers.
Lesson #3: I also suggest a fully baffled 10-qt oil pan or you run the risk of wiping out crank bearings from cornering forces. A friend lost a connecting rod after only a dozen laps of open-track road racing with a stock pan full of oil. Good luck on your next 351-C engine build.
Lesson #1 learned: do NOT bore a 351-C AT ALL unless you first run a cylinder wall thickness check. This block had a shifted casting core on that cylinder.
Lesson #2: As you found out, stock valves are made in two pieces and WILL separate at the head-to-stem weld if overstressed. And 'overstressing' is ridiculously easy on a completely stock 351-C. Air-cooled VW valves are made the same way. Use ONLY one-piece valves which require single-groove keepers.
Lesson #3: I also suggest a fully baffled 10-qt oil pan or you run the risk of wiping out crank bearings from cornering forces. A friend lost a connecting rod after only a dozen laps of open-track road racing with a stock pan full of oil. Good luck on your next 351-C engine build.
Personally, I would use 10:1 static compression ratio as the maximum. I wouldn't worry too much about whether you have 9.5 or 10.
The point is, you want to run higher then the 8.0:1 in the stock open head engines.
That's my opinion on a rebuild.
As far as a camshaft, YOU need to determine what the definition of a "street engine" is. "We" have all sorts of race and former race engines being run on street registered and street driven cars.
The old definition of "street driven" on cars like Panteras, if not all current vehicles has changed significantly since the '60s and '70s.
Few are going to use any of these cars as "everyday transportation".
In that old definition where you need to worry about being in city type traffic of bumper to bumper then I agree with GP's limit of camshaft timing.
Even that is on the "racy side" but in this limited use existence of just taking the car to a car convention, a high speed on the track event or even a "cars and coffee" thing down near the beach, limiting the cam timing is much less of a concern.
For one thing at least with a Pantera, you don't need to worry about the operation of an automatic transmission being effected by the camshaft timing.
To select a mechanical roller lifter camshaft is sentencing yourself to a "race car" type maintenance of almost daily readjustment of the valve train.
There definitely are cars running them out there but those are really falling into the definition of a "Pro-street" car.
If those types of maintenance issues don't concern you and you just want the maximum amount of hp that you can get, then yes, go for it.
Hydraulic roller lifter cams have become much more dependable and there is a greater variety of "off the shelf grinds" for you to select right now.
They are going to give you closer to a maximum hp then a flat tappet cam but the amount you gain is always going to be debatable.
Aftermarket kit components in the past or should I say initially left a lot to be desired on a dependability consideration but there are a lot of them running around the streets now with much less issue.
The main consideration is going to be the initial cost vs. a convention flat tappet cam.
I personally like solid lifter/flat tappet cams. I know how to deal with them better then the other alternatives and find that they are a better compromise as far as approaching maximum hp in a street driven car with high dependability.
I would however recommend a hydraulic lifter flat tappet cam for a true street car.
Then you could just jump into the thing, drive it anywhere and not worry about weather changes, finding racing gas along the road, and even let your daughter drive the car down to the "hamburger stand" without too much worry of being able to drive the car without a nervous break down.
By far the single most significant factor in determining the character of the car is the camshaft that you select.
Although I agree with George on the recommended timing, I'd say that you can go hotter on the cam then 236 @ 50.
What you really want to do is to limit the overlap timing on the cam to under ABOUT 70 degrees and you want a valve lift that is going to let these heads work which is going to be over .550 to as much as .625.
These 4v heads were designed to work at around .600 lift but in addition they need greater overlap then a stock camshaft. Lift and duration alone won't do it.
The more that you ask others, the more that you are going to find that the camshaft selected and LIKED is a very personal thing.
In practical terms it makes little sense to build and engine in a "street car" to run in the 8,000rpm area. If that is your criteria, then you have crossed over into the "Pro street" category.
It has and is done but it is an entirely different animal with different issues.
You actually would be better off "interviewing each CAR", experiencing how they sounded and their idle manners before you selected something.
How you are going to do that, I have no idea, but good luck on that one.
The point is, you want to run higher then the 8.0:1 in the stock open head engines.
That's my opinion on a rebuild.
As far as a camshaft, YOU need to determine what the definition of a "street engine" is. "We" have all sorts of race and former race engines being run on street registered and street driven cars.
The old definition of "street driven" on cars like Panteras, if not all current vehicles has changed significantly since the '60s and '70s.
Few are going to use any of these cars as "everyday transportation".
In that old definition where you need to worry about being in city type traffic of bumper to bumper then I agree with GP's limit of camshaft timing.
Even that is on the "racy side" but in this limited use existence of just taking the car to a car convention, a high speed on the track event or even a "cars and coffee" thing down near the beach, limiting the cam timing is much less of a concern.
For one thing at least with a Pantera, you don't need to worry about the operation of an automatic transmission being effected by the camshaft timing.
To select a mechanical roller lifter camshaft is sentencing yourself to a "race car" type maintenance of almost daily readjustment of the valve train.
There definitely are cars running them out there but those are really falling into the definition of a "Pro-street" car.
If those types of maintenance issues don't concern you and you just want the maximum amount of hp that you can get, then yes, go for it.
Hydraulic roller lifter cams have become much more dependable and there is a greater variety of "off the shelf grinds" for you to select right now.
They are going to give you closer to a maximum hp then a flat tappet cam but the amount you gain is always going to be debatable.
Aftermarket kit components in the past or should I say initially left a lot to be desired on a dependability consideration but there are a lot of them running around the streets now with much less issue.
The main consideration is going to be the initial cost vs. a convention flat tappet cam.
I personally like solid lifter/flat tappet cams. I know how to deal with them better then the other alternatives and find that they are a better compromise as far as approaching maximum hp in a street driven car with high dependability.
I would however recommend a hydraulic lifter flat tappet cam for a true street car.
Then you could just jump into the thing, drive it anywhere and not worry about weather changes, finding racing gas along the road, and even let your daughter drive the car down to the "hamburger stand" without too much worry of being able to drive the car without a nervous break down.
By far the single most significant factor in determining the character of the car is the camshaft that you select.
Although I agree with George on the recommended timing, I'd say that you can go hotter on the cam then 236 @ 50.
What you really want to do is to limit the overlap timing on the cam to under ABOUT 70 degrees and you want a valve lift that is going to let these heads work which is going to be over .550 to as much as .625.
These 4v heads were designed to work at around .600 lift but in addition they need greater overlap then a stock camshaft. Lift and duration alone won't do it.
The more that you ask others, the more that you are going to find that the camshaft selected and LIKED is a very personal thing.
In practical terms it makes little sense to build and engine in a "street car" to run in the 8,000rpm area. If that is your criteria, then you have crossed over into the "Pro street" category.
It has and is done but it is an entirely different animal with different issues.
You actually would be better off "interviewing each CAR", experiencing how they sounded and their idle manners before you selected something.
How you are going to do that, I have no idea, but good luck on that one.
quote:Originally posted by Bosswrench:
John, in autocrossing (also known as parking-lot racing), I got a backfire on the starting grid with a friend's Pantera that wasn't sufficiently warmed up. The 351-C had been rebuilt with 11:1 c.r, bored 0.030" over, big solid lifter cam & Holley carb, and needed 102 octane fuel to run without detonation. Immediately after the little backfire, water was seen running out one exhaust pipe. A teardown showed a piece of cylinder wall about 1" x 1" had cracked and blown clear into the water jacket. The retrieved piece showed a cylinder wall thickness of only 0.050"! For performance use, cylinder walls need at least 0.150" and more is better! Chev guys like to see 0.200"- no 351-C ever had such thick walls when new!
Lesson #1 learned: do NOT bore a 351-C AT ALL unless you first run a cylinder wall thickness check. This block had a shifted casting core on that cylinder.
Lesson #2: As you found out, stock valves are made in two pieces and WILL separate at the head-to-stem weld if overstressed. And 'overstressing' is ridiculously easy on a completely stock 351-C. Air-cooled VW valves are made the same way. Use ONLY one-piece valves which require single-groove keepers.
Lesson #3: I also suggest a fully baffled 10-qt oil pan or you run the risk of wiping out crank bearings from cornering forces. A friend lost a connecting rod after only a dozen laps of open-track road racing with a stock pan full of oil. Good luck on your next 351-C engine build.
I’m definitely building a library of lessons gleaned from you guys here. And having great fun reading the various anecdotes of where things have gone wrong. I can’t imagine how it must have felt to find a chunk of cylinder like that.
I promise to have the block fully sonic tested before I overbore, I know I might be able to leave it stock with just a hone, but I’m tempted to get it done along with line honing and decking so that I’ve got everything nailed down and blueprinted as best I can.
Valves, I will definitely go with the single groove, whilst I have it apart it would be madness to avoid drawing the right lessons from Sick Cats experiences.
I was looking at a road race pan, from some guys called High Energy from Australia, which is an 8 litre similar to the moroso offering, and mating it with a pressurised oil reserve unit.
Also considering getting another bare block from Aus, (as they are scandalously cheap and my company has a great shipping partner there) to use for checking fitment and clearances.
quote:Originally posted by PanteraDoug:
Personally, I would use 10:1 static compression ratio as the maximum. I wouldn't worry too much about whether you have 9.5 or 10.
The point is, you want to run higher then the 8.0:1 in the stock open head engines.
That's my opinion on a rebuild.
As far as a camshaft, YOU need to determine what the definition of a "street engine" is. "We" have all sorts of race and former race engines being run on street registered and street driven cars.
The old definition of "street driven" on cars like Panteras, if not all current vehicles has changed significantly since the '60s and '70s.
Few are going to use any of these cars as "everyday transportation".
In that old definition where you need to worry about being in city type traffic of bumper to bumper then I agree with GP's limit of camshaft timing.
Even that is on the "racy side" but in this limited use existance of just taking the car to a car convention, a high speed on the track event or even a "cars and coffee" thing down near the beach, limiting the cam timing is much less of a concern.
For one thing at least with a Pantera, you don't need to worry about the operation of an automatic transmission being effected by the camshaft timing.
To select a mechanical lifter camshaft is sentencing yourself to a "race car" type maintenance of almost daily readjustment of the valve train.
There definitely cars running them out there but those are really falling into the definition of a "Pro-street" car.
If those types of maintenance issues don't concern you and you just want the maximum amount of hp that you can get, then yes, go for it.
Hydraulic roller lifter cams have become more dependable and there is a greater variety of "off the shelf grinds" for you to select right now.
They are going to give you closer to a maximum hp then a flat tappet cam but the amount you gain is always going to be debatable.
Aftermarket kit components in the past or should I say initially left a lot to be desired on a dependability consideration but there are a lot of them running around the streets now with much less issue.
The main consideration is going to be the initial cost vs. a convention flat tappet cam.
I personally like solid lifter/flat tappet cams. I know how to deal with them better then the other alternatives and find that they are a better compromise as far as approaching maximum hp in a street driven car with high dependability.
I would however recommend a hydraulic lifter flat tappet cam for a true street car.
Then you could just jump into the thing, drive it anywhere and not worry about weather changes, finding racing gas along the road, and even let your daughter drive the car down to the "hamburger stand" without too much worry of being able to drive the car without a nervous break down.
By far the single most significant factor in determining the character of the car is the camshaft that you select.
Although I agree with George on the recommended timing, I'd say that you can go hotter on the cam then 236 @ 50.
What you really want to do is to limit the overlap timing on the cam to under ABOUT 70 degrees and you want a valve lift that is going to let these heads work which is going to be over .550 to as much as .625.
These 4v heads were designed to work at around .600 lift.
The more that you ask others, the more that you are going to find that the camshaft selected and LIKED is a very personal thing.
You actually would be better off "interviewing each CAR", experiencing how they sounded and their idle manners before you selected something.
How you are going to do that, I have no idea, but good luck on that one.
I’m not wedded to any particular static ratio so for me, I think I can live happily with ~9.5 How I can achieve it with flat tops and some milling of the head and deck or domes, I’ll keep working on figuring out, but it looks that using flat tops instead of Ross pop ups may save roughly enough to cover a hydraulic roller setup.
I very much appreciate what you are saying about Street.
When looking at Street for me, I am thinking probably roughly similar to you, that it won’t need lash adjustments at the weekend, won’t have a super rough idle, won’t be temperamentally unreliable if used to as a daily driver for a few days whilst my BMW is undergoing repairs or whatever, but it will have the capability to unleash some serious torque and HP, and maybe enjoyably compete in vintage style racing events, hill climbs and the likes, and still remain a reasonably mannered cruiser for the occasional long journey into the Scottish highlands or across Europe.
I’m not building the car as a daily driver, and again apologies gents that it’s a Mustang rather than a Pantera, much more a weekend fun car, something to be driven though rather than simply looked at.
With this I also don’t need to be worried about the auto trans, as i’m going to mate it up to a Dave Kee rebuilt RUG-JA big block toploader.
With the wise words of you and George in my mind Doug, I’m leaning very heavily towards the hydraulic roller setup and I’m going to take a more serious look at what sort of compromises and financial travails that entails during the next couple of weeks.
As for interviewing the cars to understand the cam selection, well it might have to wait until next year now, but I’ll find a way, might make for a fun vacation.
(I was also considering picking up a couple of OEM style cams from Rock auto or summit to get a feel for the changes in power bands and idle, going hydraulic might make that an expensive proposition though I suppose.)
I had a closed chamber iron head Cleveland with TRW popup pistons,compression ratio of around 11.8:1 in my 68 GT 350 for ten years or so.
I tried several cams, headers and
induction set ups.
It could never produce the power like the,current engine in my Pantera does. The chassis just created breathing issues that could not be overcome.
It needed bigger tube headers, the Webers were too close to the hood, etc.
It is also noticeably heavier then the original 302 was.
My final decision was that it wasn't worth it in a Mustang chassis.
I will say that I never blew it up either even at .030 over, although it seemed at times I was trying to really hard?
In that car I went back to the original 302 block, 4v Windsor heads, race ported with 1.94/1.60 valves. 1-3/4 tube headers, 236 @ .050 solid lifter camshaft and a 10.3:1 compression with a 347 kit and a 2x4 Holley induction.
That run in front of a Doug Nash 4+1 speed, now called a Richmond 5 speed. The 3.26 first gear does help.
It works much better then the Cleveland ever did and is about 100 pounds lighter BUT as a matter of fact, it needs more cam.
This one isn't enough. It needs to go to 1.7 ratio rocker arms for more lift.
http://www.compcams.com/Compan...s.aspx?csid=820&sb=2
The Cleveland however seems like it was made for a Pantera? Everything that makes it a killer engine fits in the car. 180 degree headers with 2" primaries, Ford A3 high port heads, Weber 48 ida carbs with 5" stacks.
I do have a lot of cam in it though. A Compcams solid lifter 294s.
http://www.compcams.com/Compan...s.aspx?csid=861&sb=2
George could give me permanent KP as a result but the way that I use the car it seems perfect?
It screams like an F1 car right off of idle.
I learned my lesson with compression ratio. My Pantera engine is a 9.5 engine.
Don't believe this business of blowing compression out of the exhaust with cam timing. Simply put, it doesn't work.
Not unless you go to RADICALLY MORE overlap where you actually hear the exhausts spitting at idle. Where that is, I'm not sure exactly but probably with a race type only cam with overlap in the mid '80s?
No matter what you do it is still the static compression ratio that determines octane since it is what determines the internal cylinder pressures.
Octane is a measure of the compressability of fuel. The higher it is, the more difficult it is to make it explode by compressing it.
As an example, diesel fuel has a much lower octane rating making it much easier to explode it by compression, which is essentially how a diesel engine runs.
I will also point out that the same camshaft in different cars, seems different.
The same cam that is in a Pantera will seem calmer in a Mustang or more radical in a Pantera.
Ford was on the right track when they produced the CJ cam for the Cleveland. The problem was that they retarded the timing in the cam itself for production and it needs more lift, a lot more to make the heads work.
George's idea of making the CJ better, or maybe correcting those oversights is actually a very good idea.
The stock sound of that CJ cam through the Pantera's Ansa mufflers actually sounds quite nice and muscular. It is not out of character to the car at all.
IF you go that route, contact the cam manufacturer and ask if the timing in their "replica" CJ cam is retarded as well.
Other than that have a great time traveling to check out how all the different cams sound?
I tried several cams, headers and
induction set ups.
It could never produce the power like the,current engine in my Pantera does. The chassis just created breathing issues that could not be overcome.
It needed bigger tube headers, the Webers were too close to the hood, etc.
It is also noticeably heavier then the original 302 was.
My final decision was that it wasn't worth it in a Mustang chassis.
I will say that I never blew it up either even at .030 over, although it seemed at times I was trying to really hard?
In that car I went back to the original 302 block, 4v Windsor heads, race ported with 1.94/1.60 valves. 1-3/4 tube headers, 236 @ .050 solid lifter camshaft and a 10.3:1 compression with a 347 kit and a 2x4 Holley induction.
That run in front of a Doug Nash 4+1 speed, now called a Richmond 5 speed. The 3.26 first gear does help.
It works much better then the Cleveland ever did and is about 100 pounds lighter BUT as a matter of fact, it needs more cam.
This one isn't enough. It needs to go to 1.7 ratio rocker arms for more lift.
http://www.compcams.com/Compan...s.aspx?csid=820&sb=2
The Cleveland however seems like it was made for a Pantera? Everything that makes it a killer engine fits in the car. 180 degree headers with 2" primaries, Ford A3 high port heads, Weber 48 ida carbs with 5" stacks.
I do have a lot of cam in it though. A Compcams solid lifter 294s.
http://www.compcams.com/Compan...s.aspx?csid=861&sb=2
George could give me permanent KP as a result but the way that I use the car it seems perfect?
It screams like an F1 car right off of idle.
I learned my lesson with compression ratio. My Pantera engine is a 9.5 engine.
Don't believe this business of blowing compression out of the exhaust with cam timing. Simply put, it doesn't work.
Not unless you go to RADICALLY MORE overlap where you actually hear the exhausts spitting at idle. Where that is, I'm not sure exactly but probably with a race type only cam with overlap in the mid '80s?
No matter what you do it is still the static compression ratio that determines octane since it is what determines the internal cylinder pressures.
Octane is a measure of the compressability of fuel. The higher it is, the more difficult it is to make it explode by compressing it.
As an example, diesel fuel has a much lower octane rating making it much easier to explode it by compression, which is essentially how a diesel engine runs.
I will also point out that the same camshaft in different cars, seems different.
The same cam that is in a Pantera will seem calmer in a Mustang or more radical in a Pantera.
Ford was on the right track when they produced the CJ cam for the Cleveland. The problem was that they retarded the timing in the cam itself for production and it needs more lift, a lot more to make the heads work.
George's idea of making the CJ better, or maybe correcting those oversights is actually a very good idea.
The stock sound of that CJ cam through the Pantera's Ansa mufflers actually sounds quite nice and muscular. It is not out of character to the car at all.
IF you go that route, contact the cam manufacturer and ask if the timing in their "replica" CJ cam is retarded as well.
Other than that have a great time traveling to check out how all the different cams sound?
You’re making me like the sound of the Pantera more and more Doug
I should be able to get some pretty decent hooker headers into the ‘70 stang which might alleviate some of the problems you note, I probably still won’t get what you get from it thanks to weight and weight distribution as much as anything else, and I might actually drop in a 2v Windsor (was original H code) and keep the 351c aside when I eventually sell up. (I’ve half an eye on restoring a 71 convertible eventually and that’s got quite a bit more space under the hood a Pantera being way out of my price range for now)
Just to pull back a little to something George said in the original post:
‘It is my hope that someday soon a manufacturer shall offer a steel bodied pedestal mount rocker arm.’
In lieu of that eventually happening, I’ve come across an Aussie bunch called Crow Cams offering steel roller rockers for the Cleveland (screw in stud and plate, 7/16, 1.7 ratio, ironically more info on eBay than their site) anyone had any experience with these fellows? As I guess they’d well outlast the Aluminium versions and the price looks okay.
I should be able to get some pretty decent hooker headers into the ‘70 stang which might alleviate some of the problems you note, I probably still won’t get what you get from it thanks to weight and weight distribution as much as anything else, and I might actually drop in a 2v Windsor (was original H code) and keep the 351c aside when I eventually sell up. (I’ve half an eye on restoring a 71 convertible eventually and that’s got quite a bit more space under the hood a Pantera being way out of my price range for now)
Just to pull back a little to something George said in the original post:
‘It is my hope that someday soon a manufacturer shall offer a steel bodied pedestal mount rocker arm.’
In lieu of that eventually happening, I’ve come across an Aussie bunch called Crow Cams offering steel roller rockers for the Cleveland (screw in stud and plate, 7/16, 1.7 ratio, ironically more info on eBay than their site) anyone had any experience with these fellows? As I guess they’d well outlast the Aluminium versions and the price looks okay.
1.7 in the same ratio as used on Big block Chevy's. Readily available.
Mark
Mark
John, 2024-extruded aluminum roller rockers will work just fine on the street, with the following provisos: 1- use brand name assemblies. Cheap far-east copies are of doubtful metallurgy; we call the stuff 'chinesium'. 2- Use NON-racing valve springs and 3- a 6500 rpm redline. Exceed either the spring strength or rpms very much, for very long or very often, and steel roller rockers (several good makers) are almost mandatory. Most 'steel' rockers are investment-cast-stainess, by the way.
i don't think anyone's talking about controlling DCR during the overlap period (intake valve opening) but rather when the intake valve closes ... when the actual physical act of compressing whatever is in the cylinder begins and the exhaust valve has been closed for quite some time
but as far as overlap barking at idle, Yes the Crane F238 barks sharply when the throttle is snapped
by no means a nice driving cam, the F238 trades idle & low speed characteristics for high speed scavenging which i believe it does pretty darn good! FWIW the F238 has less lift more overlap than the F246
but as far as overlap barking at idle, Yes the Crane F238 barks sharply when the throttle is snapped
by no means a nice driving cam, the F238 trades idle & low speed characteristics for high speed scavenging which i believe it does pretty darn good! FWIW the F238 has less lift more overlap than the F246
John H,
Aftermarket rocker arms fall into two categories; (1) those that mount on studs and are laterally positioned by their push rods using guide plates, (2) those that are mounted rigidly to the cylinder head and are laterally positioned by the orientation of their mounting system. The second type of rocker arm is described by several names: individual shaft mount, pedestal mount, saddle mount, or bolt down. Whatever they may be called they have two things in common, they mount rigidly to the cylinder head and they are equipped with threaded push-rod cup style adjusters for solid tappet lash adjustment or hydraulic tappet compression adjustment.
Rigidly mounted rocker arms are preferred because they have several advantages in comparison to stud mounted rocker arms: rocker arm geometry is not dependent upon the length of the push rod, rocker arm geometry is not altered during lash adjustment, rocker arm geometry is easier to set because it can be set while the cylinder head is sitting on a work bench, and the mounting system is more stable thus eliminating any rocker arm induced valve train instability problems. T&D rocker arms are supplied with a "Stand Height Gage" to aid in setting rocker arm geometry.
Pressurized oil is supplied to all rocker arms via the pushrod. Most rocker companies have a through hole in the push rod cup or the push rod cup adjuster screw. The through hole allows oil to spray out the top of the cup or the adjuster, the oil hits the valve cover, and then rains down on the rocker arms.
By contrast T&D rocker arms are internally lubricated. Oil supplied by the push rod to the push rod cup adjuster screw makes a 90° turn and enters the rocker body itself. An oil passage within the rocker arm body routes the oil between the two bearings in the rocker and then out to the opposite end of the rocker arm where it sprays against the backside of the roller tip. T&D rocker arms thus have engine oil pressure right to the fulcrum bearings; bearing issues are a rare occurrence with T&D rocker arms.
All aluminum rocker arms will eventually fail from fatigue, even those made from billet aluminum. This is true with anything made of aluminum that cycles. Aluminum rocker arm failure is predominantly a function of cycle time. They cycle faster at high rpm, but even at idle the rocker arms are being cycled. Valve lift has nothing to do with rocker fatigue what so ever. Valve spring force should not be a significant factor since the topic at hand is performance street engines which are generally limited to 400 pounds over the nose (or less) in the name of valve train longevity.
T&D aluminum rocker arms have the highest cycle time in the rocker arm industry ... BUT... T&D rocker arms are also the only rigidly mounted rocker arms which at this time are available optionally with a steel rocker arm body for the best possible longevity. While other rocker arm companies manufacture stud mounted rocker arms made of cast steel, T&D’s steel rocker arm bodies are machined from billet chromoly steel, their cycle time life is almost infinite.
If the T&D rocker arms are outside of a person’s budget I have two other recommendations, both are rigidly mounted billet aluminum rocker arms. If the cylinder heads have already been machined for 7/16 studs and guide plates the Yella Terra YT6321 rocker arms will mount solidly to the machined pedestals in place of the studs and guide plates. Yella Terra sells saddles of varying height to aid in setting the rocker arm's geometry. If the cylinder heads are unmodified, still equipped with slotted rocker arm pedestals, the Scorpion part no. 3224 rocker arms mount to slotted pedestals with 5/16 Allen bolts. Shims are available to aid in setting the rocker arm geometry of pedestal mounted rocker arms such as these.
In terms of stud and guide plate rocker arms ... you're on your own.
In terms of BBC rocker arms, the distance from mounting stud to valve tip is 0.025" greater, and the push rod cup end is 21 degrees askew ...
Aftermarket rocker arms fall into two categories; (1) those that mount on studs and are laterally positioned by their push rods using guide plates, (2) those that are mounted rigidly to the cylinder head and are laterally positioned by the orientation of their mounting system. The second type of rocker arm is described by several names: individual shaft mount, pedestal mount, saddle mount, or bolt down. Whatever they may be called they have two things in common, they mount rigidly to the cylinder head and they are equipped with threaded push-rod cup style adjusters for solid tappet lash adjustment or hydraulic tappet compression adjustment.
Rigidly mounted rocker arms are preferred because they have several advantages in comparison to stud mounted rocker arms: rocker arm geometry is not dependent upon the length of the push rod, rocker arm geometry is not altered during lash adjustment, rocker arm geometry is easier to set because it can be set while the cylinder head is sitting on a work bench, and the mounting system is more stable thus eliminating any rocker arm induced valve train instability problems. T&D rocker arms are supplied with a "Stand Height Gage" to aid in setting rocker arm geometry.
Pressurized oil is supplied to all rocker arms via the pushrod. Most rocker companies have a through hole in the push rod cup or the push rod cup adjuster screw. The through hole allows oil to spray out the top of the cup or the adjuster, the oil hits the valve cover, and then rains down on the rocker arms.
By contrast T&D rocker arms are internally lubricated. Oil supplied by the push rod to the push rod cup adjuster screw makes a 90° turn and enters the rocker body itself. An oil passage within the rocker arm body routes the oil between the two bearings in the rocker and then out to the opposite end of the rocker arm where it sprays against the backside of the roller tip. T&D rocker arms thus have engine oil pressure right to the fulcrum bearings; bearing issues are a rare occurrence with T&D rocker arms.
All aluminum rocker arms will eventually fail from fatigue, even those made from billet aluminum. This is true with anything made of aluminum that cycles. Aluminum rocker arm failure is predominantly a function of cycle time. They cycle faster at high rpm, but even at idle the rocker arms are being cycled. Valve lift has nothing to do with rocker fatigue what so ever. Valve spring force should not be a significant factor since the topic at hand is performance street engines which are generally limited to 400 pounds over the nose (or less) in the name of valve train longevity.
T&D aluminum rocker arms have the highest cycle time in the rocker arm industry ... BUT... T&D rocker arms are also the only rigidly mounted rocker arms which at this time are available optionally with a steel rocker arm body for the best possible longevity. While other rocker arm companies manufacture stud mounted rocker arms made of cast steel, T&D’s steel rocker arm bodies are machined from billet chromoly steel, their cycle time life is almost infinite.
If the T&D rocker arms are outside of a person’s budget I have two other recommendations, both are rigidly mounted billet aluminum rocker arms. If the cylinder heads have already been machined for 7/16 studs and guide plates the Yella Terra YT6321 rocker arms will mount solidly to the machined pedestals in place of the studs and guide plates. Yella Terra sells saddles of varying height to aid in setting the rocker arm's geometry. If the cylinder heads are unmodified, still equipped with slotted rocker arm pedestals, the Scorpion part no. 3224 rocker arms mount to slotted pedestals with 5/16 Allen bolts. Shims are available to aid in setting the rocker arm geometry of pedestal mounted rocker arms such as these.
In terms of stud and guide plate rocker arms ... you're on your own.
In terms of BBC rocker arms, the distance from mounting stud to valve tip is 0.025" greater, and the push rod cup end is 21 degrees askew ...
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Hi from France,
I haven't found any section I should introduce myself first before to post Something else. By the way, If it exist please tell me.
First of all, I am French and write English very badly, please excuse me.
I just bought the Pantera L 1972 #4406, I know it comes from the USA but I have no history. If anyone from this forum knows anything about it i will be happy to know more about it.
This subject interests me a lot since it has a 351 C with an open 4V cylinder head.
I did not read everything line by line because it's hard for me to understand English and
unfortunately, I don't understand all the acronyms and I would be very grateful if you would indicate to me the full expression of:
- BSFC
- SCJ (.....Predicted performance)
- fps (feet per second?)
Thank you
I haven't found any section I should introduce myself first before to post Something else. By the way, If it exist please tell me.
First of all, I am French and write English very badly, please excuse me.
I just bought the Pantera L 1972 #4406, I know it comes from the USA but I have no history. If anyone from this forum knows anything about it i will be happy to know more about it.
This subject interests me a lot since it has a 351 C with an open 4V cylinder head.
I did not read everything line by line because it's hard for me to understand English and
unfortunately, I don't understand all the acronyms and I would be very grateful if you would indicate to me the full expression of:
- BSFC
- SCJ (.....Predicted performance)
- fps (feet per second?)
Thank you
Hello René, welcome aboard the De Tomaso forums. 
There are 29 forums here, one for just about every possible subject. The forums summary page lists all of them, plus a description of their content, to help you figure-out where to search for content, or where to start a new topic (thread).
BSFC = Brake Specific Fuel Consumption. "Brake" is another name for a dynamometer. Besides horsepower and torque, engines tested on dynamometers are usually monitored for volumetric efficiency and BSFC. BSFC is an indicator for thermal efficiency and mechanical efficiency. With BSFC the smaller numbers are better, and an engine's best BSFC usually occurs at peak torque.
SCJ = Super Cobra Jet. Ford used this name for special ordered solid tappet versions of their 1969 - 1971 Cobra Jet engines; the 428 Cobra Jet and the 429 Cobra Jet. I use the term to denote a very "hot" street camshaft, or a very "hot" street engine equipped with such a camshaft.
fps (feet per second?) = Yes feet per second. A foot is 304.8mm.
.
There are 29 forums here, one for just about every possible subject. The forums summary page lists all of them, plus a description of their content, to help you figure-out where to search for content, or where to start a new topic (thread).
BSFC = Brake Specific Fuel Consumption. "Brake" is another name for a dynamometer. Besides horsepower and torque, engines tested on dynamometers are usually monitored for volumetric efficiency and BSFC. BSFC is an indicator for thermal efficiency and mechanical efficiency. With BSFC the smaller numbers are better, and an engine's best BSFC usually occurs at peak torque.
SCJ = Super Cobra Jet. Ford used this name for special ordered solid tappet versions of their 1969 - 1971 Cobra Jet engines; the 428 Cobra Jet and the 429 Cobra Jet. I use the term to denote a very "hot" street camshaft, or a very "hot" street engine equipped with such a camshaft.
fps (feet per second?) = Yes feet per second. A foot is 304.8mm.
.
I am running "Fat Boy" aluminum 1.73 rocker arms (Crane) They have given around 50,000 miles trouble free with lifts over 600, hydraulic rollers and have been in 3 different rebuilds, the current engine was professionally rebuilt ( B L machine Russ Fulp) and I had the builder check them, he said they were good? These rockers have steel insertion both ends large trunnion.
Thank you for your welcome
Brake Specific Fuel Consumption, okay, that I understand and I know what it is.
You say that the walls of the cylinders are thin and they have a reputation for cracking under demanding use, so it isn't a good idea to bore to 4.03" as it's proposed in many stroker kits?
Brake Specific Fuel Consumption, okay, that I understand and I know what it is.
You say that the walls of the cylinders are thin and they have a reputation for cracking under demanding use, so it isn't a good idea to bore to 4.03" as it's proposed in many stroker kits?
some blocks have serious 'core shift' that leaves one side of the cylinder very thin, a sonic check can determine if you block has a thin wall and is not a good candidate to be bored & built to high output
http://arengineering.com/tech/how-to-sonic-checker/
http://arengineering.com/tech/how-to-sonic-checker/
I do not agree with the philosophy of automatically boring a block to 4.030. I believe it should be honed or bored to size, just enough to clean-up the cylinder walls. Many blocks can be cleaned-up with 4.010 bores. Of course, this means having to custom order the pistons. This is no "big deal" as far as I'm concerned, but convincing some people to consider custom ordering pistons is difficult.
No stroker kit offers pistons with full round skirts. As far as I'm concerned that means limiting engine speed to whatever is equivalent to 3600 fpm piston speed. To go beyond 3600 fpm piston speed I recommend full round skirt pistons. Nor do I agree with a rod length to stroke ratio less than 1.6:1, wrist pins that intersect the oil ring groove, or pulling the wrist pin out of the bottom of the bore at BDC. In other words, the only stroker kit I can agree with is 3.75 stroke with a 6" connecting rod.
No stroker kit offers pistons with full round skirts. As far as I'm concerned that means limiting engine speed to whatever is equivalent to 3600 fpm piston speed. To go beyond 3600 fpm piston speed I recommend full round skirt pistons. Nor do I agree with a rod length to stroke ratio less than 1.6:1, wrist pins that intersect the oil ring groove, or pulling the wrist pin out of the bottom of the bore at BDC. In other words, the only stroker kit I can agree with is 3.75 stroke with a 6" connecting rod.