Tom E of Tennessee had some questions about 351C engine building ...
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quote:Originally posted by Cowboy from Hell:quote:story by news-journalonline.com:
Deal pending to reopen Crane Cams
Staff Report
Scorpion Performance Inc., a company negotiating to buy Crane Cams, is staging a job fair for former Crane employees at 9:30 a.m. Thursday at Crane’s Fentress Boulevard facility, a company official said today.
Scorpion officials have been negotiating to buy Crane for more than a week. Crane closed in late February, leaving about 280 workers without jobs.
"We cannot promise everyone will get their old job back, but all positions will need to be filled," said Scott Reynolds, Scorpion vice president of marketing. "We would like all attendees to bring their resumes detailing what functions they performed at Crane."
Reynolds said food and drinks will be available. The event is not open to the public.
Dear George, wasn't Crane cams like the best cam money could buy? If I remeber right them and Iscyandarian(SP?) were like the best quality and all that.
Also I got a question about CJ spec clevelands. I had heard that along with dropping the compresion ratio a whole ton, they also retarded the cam by four degrees to pass smog tests. Wouldn't just taking the cam out and turning it back four degrees without doing nothing else make you engine livelier??????
quote:Also I got a question about CJ spec clevelands. I had heard that along with dropping the compresion ratio a whole ton, they also retarded the cam by four degrees to pass smog tests. Wouldn't just taking the cam out and turning it back four degrees without doing nothing else make you engine livelier??
Maybe- depending on the combination of parts inside your engine. What Ford did in late '72 was to retard the camshaft 4 or so degrees by changing the silent-chain crank sprocket's keyway location. Changing cam advance only shifts the powerband up or down the rev-range; it normally doesn't increase it. All aftermarket roller cam chains recommended for 351Cs have multiple keyway slots for those who want to tune their engines. Decades ago, builders used the 4 degree advance key-slot to compensate for expected chain stretch after 500 miles, but nowadays with modern cams and better quality cam chains, 'some' extra advance is already built in by the cam grinder. So I don't advocate blindly cranking in more cam advance without first checking as to what the effect will be on power, or valve-to-piston clearances. Dyno-tuning an engine pays many dividends.
quote:Originally posted by Bosswrench:quote:Also I got a question about CJ spec clevelands. I had heard that along with dropping the compresion ratio a whole ton, they also retarded the cam by four degrees to pass smog tests. Wouldn't just taking the cam out and turning it back four degrees without doing nothing else make you engine livelier??
Maybe- depending on the combination of parts inside your engine. What Ford did in late '72 was to retard the camshaft 4 or so degrees by changing the silent-chain crank sprocket's keyway location. Changing cam advance only shifts the powerband up or down the rev-range; it normally doesn't increase it. All aftermarket roller cam chains recommended for 351Cs have multiple keyway slots for those who want to tune their engines. Decades ago, builders used the 4 degree advance key-slot to compensate for expected chain stretch after 500 miles, but nowadays with modern cams and better quality cam chains, 'some' extra advance is already built in by the cam grinder. So I don't advocate blindly cranking in more cam advance without first checking as to what the effect will be on power, or valve-to-piston clearances. Dyno-tuning an engine pays many dividends.
Thank you Mr. Bosswrench. I bought the engine back in 2005 and it was a remanufactured CJ spec engine, and just like you said, at 500 miles the timing suddenly got real retarded so I had to twist the ditributor. Now I have close to 1000 miles on it and I am kind of missing the previous euro-spec engine it had in it, but since that one went to heaven, I can't just put it back. But I did save the old closed chamber heads, so I was thinking of sticking those on my CJ spec engine instead of the no compression wide open chamber boat anchors that are on there now, and while I was at it, maybe tweak the cam a little, like maybe four teeth or whatever and just see if it ran better when I put it all back together again. I am sure Dynos are real good to have around, but I doubt I will ever get around to owning something like that. Heck I am lucky to have the right size wrench most the time, let alone any fancy tools like that.
DeTom I'm doing exactly what you are doing..but going a bit farther. I have a Dec 72 car, #4382. I'm swapping the open chamber heads to 71 closed chamber with new valves(lighter,one piece, better flow), roller rockers(less friction), new behive springs(less mass in the retainer) and am cleaning up the intake and exhaust bowls, reworking the short side radius in the exhaust chamber(per recommendations of Dan Jones). Also new cam and high quality double roller timing chain set without the 4 degrees of retard on the new cam. I'm changing intake manifold and carb...just haven't chosen them yet. It will be very interesting to see how the motor perform with the changes.
quote:Originally posted by Tom@Seal Beach:
DeTom I'm doing exactly what you are doing..but going a bit farther. I have a Dec 72 car, #4382. I'm swapping the open chamber heads to 71 closed chamber with new valves(lighter,one piece, better flow), roller rockers(less friction), new behive springs(less mass in the retainer) and am cleaning up the intake and exhaust bowls, reworking the short side radius in the exhaust chamber(per recommendations of Dan Jones). Also new cam and high quality double roller timing chain set without the 4 degrees of retard on the new cam. I'm changing intake manifold and carb...just haven't chosen them yet. It will be very interesting to see how the motor perform with the changes.
Please Mr. Seal, let me know how it turns out. I am thinking light weight valve train and keeping spring forces down to put less strain on the cam drive as a way for quicker revs too. I would be most interested in your results.
De Tom,
How much money you willing to spend?...I'd really like to go with titanium valves and retainers...but that would probably ad a few grand to the price, plus not sure about longevity of those valves.
I recall that Manly has some sodium filled and hollow stem Stainless valves that would lower the weight a bit also. I don't plan on going much above 6000r's so what I'm doing is fine. I should be able to get away with a 150 pound closed seat pressure and 350 open. My cam will be under .600 lift....a nice street motor that hopefully should live a good, long, tormented life.
How much money you willing to spend?...I'd really like to go with titanium valves and retainers...but that would probably ad a few grand to the price, plus not sure about longevity of those valves.
I recall that Manly has some sodium filled and hollow stem Stainless valves that would lower the weight a bit also. I don't plan on going much above 6000r's so what I'm doing is fine. I should be able to get away with a 150 pound closed seat pressure and 350 open. My cam will be under .600 lift....a nice street motor that hopefully should live a good, long, tormented life.
Well Dan Jones said he had a spare set of Titanium valves for 50 bucks a piece. I am just saving up some money to get a deal like that. Yep, I was going to go real light and like you keep lift to aroun .58" and keep the entire thing light. That is why I am avoiding roler cam and lifters cause they add weight. Weight adds strees and robs horsepower. I was going maybe some anti-pump hydraulic lifters, maybe some sodium filled pushrods maybe, but just keep shopping to get it on sale as I am not in a big hurry.
I like the way Chapman thought. "Add lightness".
I like the way Chapman thought. "Add lightness".
quote:DeTom, you said you are not going with roller tappets to keep weight down...I didn't think about that. What's worse the friction from a flat tapped or the extra weight of a roller lifter with less friction? My cam lift will be similar to DeToms at .580 ballpark. I'm using behive springs with steel retainers.
http://www.coasthigh.com/product-p/scp1024.htm
As long as you have good lubrication the friction for both is about the same because it is the oil film that it slides across. They use rollers to allow more agresive valve opening, in that they can make the ramps on the cam itself steeper if a roller is used because a flat tappet would bind on too step of a surface. Even at the same lift a roller tappet CAM will force open the valve farther, faster in the opening phase but will require more force to do so. It can also hold the valve open at full lift longer because it has a steeper ramp there too, but here again, you have to have more spring force to get the valve to accelerate faster. There is an advantage in volumetric efficiency, but it also beats up the valvetrain quicker because higher force loadings are involved. I like the idea of slightly increased power without sacrificeing longterm longevity. But then again, I am happy with 375-350 horsepower. Most folks no a days demand a thousand. I am not all that greedy myself.
DeTom, I think your horsepower numbers are off/low...I've seen actual dyno printout in late October of 2008 on .030 over 351C with cam lift similar to what you and I are talking, 10-1 compression, etc. This config should easily push you into the mid 400+ hp range. PM me your email address and I will email you the dyno chart that shows between 456-483 hp 5500 to 6500 rpm. I am getting exact cam spec, and head config and I will also forward that onto you. The reference motor is using a Holley Strip Dominator which I understand can be worth 30-40hp.
DeTom, here's a reasonable engine build using factory parts as much as possible. This criteria establishes a foundation that you can build upon to make anything from a durable hot street motor to a serious race motor. The budget needed to accomplish this work is the minimum budget I recommend spending in order to have the peace of mind that a thorough job of preparation has been performed.
____________________________________________________________
Short Block
Stock Displacement, 351 to 357 cubic inches
(1) OEM block
(A) Align honing if needed
(B) Cylinder boring if needed (avoid going more than 0.030” over). If the cylinders are bored they should be "indexed" to the crankshaft centerline during the boring process.
(C) Cylinder honing as per the ring manufacturer's spec, with head plates and main caps torqued in place.
(D) Decks milled the minimum amount that levels them front to back and equalizes their height side to side. Clevelands are normally decked 0.012" to 0.015" (nominal) but please avoid decking them any more than that. If they are decked more than that it becomes difficult to achieve the compression ratio goal for a street engine.
(2) OEM crankshaft. If the journals of a nodular iron crankshaft are ground undersize the journals MUST be polished afterwards. Polishing & tuftriding are a good idea anyway to better lubricate the journals and to better cope with the heavy duty bearings which have less "imbed-abilty" than standard bearings.
When a machinist hones the main bearing saddles in the block or grinds the crankshafts journals its imperative to double check the work for taper and concentricity with gauges capable of measuring 0.0001".
(3) OEM rods
(A) Install ARP bolts & nuts
(B) Resize the big end
(4) Forged Flat Top pistons TRW (L2379F) or Ross (full round skirts). The round skirts of the Ross pistons spread thrust loads and greatly help to prevent cylinder wall cracking, they are the better choice. They are also designed for thinner rings and wrist pin oiling.
(5) Lightweight steel flywheel (~30 pounds or less)
(6) New crank dampener, a nice fat one (i.e. heavy) like the Boss 351 damper. Steel hub & steel ring, fully bonded. An ATI damper or a BHJ Dynamics damper are both really good choices. The Romac damper is not fully bonded but it is a good damper and a bit less expensive.
(7) Dynamic balance the reciprocating assembly (not the same as internal balancing)
(8) New top quality, hand fitted rings (Hastings, Total Seal, Speed Pro)
(9) Clevite 77 main & rod bearings
>The 351C does not have a defective cooling system. Its cooling system was advanced for its day, and it requires a specific high-flow thermostat to operate properly. That thermostat was unusual for its day, it was not designed the same as the thermostat used in any other American V8. That’s where the problem lies, as most parts counters supply a Windsor thermostat to 351C customers, which is the wrong thermostat.
(10) A Robertshaw 333-180 thermostat (Summit #BRA-333-180) is the correct OEM thermostat. Install no other thermostat in your 351C.
(11) Flow Kooler coolant pump increases flow at low rpm, a good idea for a Pantera. Stewart Components stage 4 351W racing coolant pump can be modified to fit the 351C and offers 4 times higher flow capacity (its rated to flow 160 gpm!).
(12) Rubber rear crankshaft seal (OEM seal was made of rope). Remove the small pointed pin in the seal groove of the #5 main bearing cap.
_______________________________________________________________
Cleveland Lubrication 101
(1) Install Moroso #22050 oil restrictor kit for all 5 cam bearings (0.060”) this requires two kits to achieve enough small restrictors. Do not use the larger restrictor in the left side lifter oil passage. The restrictor for cam bearing #1 requires "special" installation. It is not installed in the same manner as the other 4, if it were it would limit oil to the #1 main bearing. It must be installed deeper within the oil passage.
(2) Install a new standard volume oil pump, Melling #M84A, NAPA #601-1024. The standard 351C oil pump is actually a high volume oil pump, it has a taller rotor than the oil pumps in other Ford V8s. However, if you're not going to install tappet bore bushings a high volume pump "may" improve crank bearing lubrication. I wrote "may" because many lubrication system modifications are fuzzy and theoretical, whereas installing the tappet bore bushings is a "sure" thing.
(3) Fully grooved main bearings (requires using the upper shells from two bearing sets).
(4) Set the bearing clearances properly. Approximately 0.001" clearance per inch of journal diameter. Its usual to run the mains a bit "tight" and the rods a bit "loose" in a 351C.
(5) If you're just going to cruise, never drive your car fast, you can make-do using the factory oil pan. If you are using the factory oil pan, use one with a built-in windage tray, or install an aftermarket windage tray. Cars that are driven fast in corners, accelerated fast, and stopped fast really need a high capacity racing pan with baffles, hinged doors, a windage tray and a scraper. It should be designed to fit in the specific chassis where the motor will be installed & for the intended usage of the vehicle. Pantera oil pan: Armando #404 or Aviaid #155-55365.
(6) Use the high volume oil pump pick-up with the factory oil pan. It was standard equipment in the Boss 351 & 351 Cobra Jet versions. Or use the pick-up provided with the high capacity oil pan.
(7) Install tappet bore bushings to control oil flow to the valve train and improve bearing lubrication. If tappet bore bushings are not installed oil flow to the valve train must be controlled either via oil restricting solid flat tappets, or via push rods with 0.040" restrictors in one tip for hydraulic valve train. Solid roller tappets must use the bushings.
___________________________________________________________
Heads
(1) Select either 1970 (D0AE) or 1971 (D1AE) closed chamber 4V heads. The D0AE heads are best with stock pin height pistons (like the TRW flat tops) and an un-decked block, or for building more dynamic compression with a cam that closes the intake valve later than 70 degrees ABDC. The D1AE head is best with an increased pin height piston (like the Ross pistons) and/or a decked block. The goal for an engine operating on 91 octane pump gas is about 7.6:1 or 7.7:1 dynamic compression.
(2) One piece, single groove, stainless steel valves: Manley Race Master intake and Severe Duty exhaust. Do not use the OEM valves as they have a reputation for dropping the valve heads while the motor is running.
(3) Bronze valve guides
(4) Repair of any recessed valves
(5) Valve springs with about 120 pounds seated force, 330 pounds over the nose (for flat tappet camshafts). Use steel spring cups, titanium spring keepers for the intake valves, chromoly spring keepers for the exhaust valves.
(6) Factory rocker arms & steel fulcrums (4V fulcrums) are OK for hydraulic cams up to about 0.550" net lift. Stronger (ARP) fasteners for the fulcrums are good insurance against "bolt-stretch" because the fulcrum bolts are only 5/16". If you need a better rocker arm, or adjustable valve train consider machining the rocker pedestals and using Yella Terra YT6321 rocker arms. I like the T&D Machine rockers, but they're even more expensive than the Yella Terra rockers. I don't personally use or recommend push-rod guided rocker arms.
(7) Typical Cleveland port work is recommended but not mandatory: this includes bowl clean-up, multi-angle valve seat profiling, exhaust port porting & a bit of valve unshrouding in the combustion chamber. Obviously the more power you expect to make, the more porting such as this will help you achieve your goal.
_________________________________________________________________
Camshaft
(1) Three choices:
(A) Select a Cobra jet camshaft; specs are 270/290 duration, 0.481"/0.490" lift. Set it at 117 degree intake centerline (factory cam) or 115 degree intake centerline (aftermarket replacement).
(B) Ford offered a hotter flat tappet hydraulic camshaft #D1ZZ-6250-BX which was basically a hydraulic tappet version of the Boss 351 cam. It was once a very popular cam, it is available today from a few aftermarket suppliers such as Melling (#24224). The cam specs are 290/290 advertised duration (219/219 @ 0.050), 0.505”/0.505” lift, 114 degree LSA. This cam has 62 degrees overlap, which is about as much overlap as you ever want for a street engine; FYI the 351 Boss camshaft had 58 degrees overlap.
(C) Have a cam custom ground to this spec: 276/286 advertised duration, 112 degree intake centerline, 117 degree exhaust centerline. 52 degrees overlap, exhaust valve opens at 80 degrees BBDC, intake valve closes at 70 degrees ABDC. Net valve lift in the range of 0.550" to 0.600" depending upon the lobes chosen.
(2) Speed Pro HT900 hydraulic flat tappets.
(3) Seamless chrome moly tubing push rods. 3/8 diameter 0.080” wall, or 5/16” diameter 0.116" - 0.120" wall.
(4) Steel timing chain set, 9 keyway crank sprocket. Such as Roll Master #CS3091
(5) Be sure to use motor oil with excellent anti-wear properties, such as Valvoline VR1 10W30 or 20W50
_________________________________________________________________
Ignition
(1) Rebuilt & recurved Duraspark distributor (sourced from a 1977 – 1982 351M, 400 or 460). The MSD distributor with vacuum advance is a good substitute, it uses the same magnetic pick-up as the Ford distributor.
(2) Duraspark I module (sourced from a 1977 – 1979 California vehicle with a 302 V8)
(3) Duraspark I coil. No substitutes.
(4) Duraspark II wiring harness: Painless Wiring #30812, requires a bit of modifying for the Duraspark I module & coil.
____________________________________________________________________
Fuel System
(1) Blue Thunder dual plane intake manifold. This manifold was originally designed by Ford engineers.
(2) Holley style 750 CFM carburetor with annular booster venturis. Plus street-performance calibration and electric choke. I recommend vacuum secondaries, but some guys will prefer mechanical secondaries (double pumper carbs).
(3) Robb Mc Performance #1020 mechanical fuel pump (good for up to 550 BHP). Groovy part, groovy company. "Fat" oil filters hit the fuel pump.
(4) Panteras need to increase the size of the tubing supplying the fuel pump.
______________________________________________________________________
Exhaust
(1) 4V Headers (1-7/8” to 2” primaries)
(2) Low restriction tail pipes (2-1/4" through 2-1/2") and mufflers.
Pantera exhaust: Don't use the OEM Ford Spec exhaust, the European GTS exhaust is a good recommendation. A cam which opens the exhaust valve early helps the engine cope with the small ANSA mufflers.
______________________________________________________________
From a Strong Performer to a Wild Child
This engine will run forever in this state of tune. It has a mild burble at idle, like any muscle car era factory performance motor did. It has lots of vacuum at idle, peak BHP will be about 365 at 5800 RPM with the Cobra Jet cam, 20 more with the 290/290 hydraulic cam. It has a very enjoyable, street friendly, wide, power band. The limiting factor to this motor's power is the relatively low lift camshaft. Substitute a higher lift (low overlap, wide LSA) custom ground cam and power over 400 bhp is easily attainable with good drivability. This is more than ample power to go fast and push the limits of traction with street tires.
Substitute a solid tappet cam, and matching tappets and valve springs. Increase the size of the carburetor to an 850 Holley; and install a hotter exhaust system and this same build shall make 500 BHP on pump gas. The Holley Strip Dominator intake manifold will return better numbers at peak horsepower and at high rpm, but I don't recommend it for a street engine, and I would personally prefer the mid-range of the dual plane manifold even for circuit racing. With a set-up like this pushing the motor to operate at higher RPM, the 351C turns into a wild child. Better connecting rods are usually part of an engine in this state of tune.
_____________________________________________________________
“A Man’s Gotta Know His Limitations” … Dirty Harry
Enthusiasts competing in drag racing with the 351C get away with making over 600 horsepower without failure of the OEM block or crankshaft; enthusiasts competing in circle track and road course racing with the 351C are not as fortunate however, for that type of competition I recommend setting 500 horsepower & 7000 rpm as your limit if you plan to use OEM block and/or OEM crankshaft. If you want to make more than 500 horsepower I suggest using an aftermarket block with thick cylinder walls and thick bulk heads, an internally balanced and fully counter-weighted steel crank, and better connecting rods.
____________________________________________________________
Short Block
Stock Displacement, 351 to 357 cubic inches
(1) OEM block
(A) Align honing if needed
(B) Cylinder boring if needed (avoid going more than 0.030” over). If the cylinders are bored they should be "indexed" to the crankshaft centerline during the boring process.
(C) Cylinder honing as per the ring manufacturer's spec, with head plates and main caps torqued in place.
(D) Decks milled the minimum amount that levels them front to back and equalizes their height side to side. Clevelands are normally decked 0.012" to 0.015" (nominal) but please avoid decking them any more than that. If they are decked more than that it becomes difficult to achieve the compression ratio goal for a street engine.
(2) OEM crankshaft. If the journals of a nodular iron crankshaft are ground undersize the journals MUST be polished afterwards. Polishing & tuftriding are a good idea anyway to better lubricate the journals and to better cope with the heavy duty bearings which have less "imbed-abilty" than standard bearings.
When a machinist hones the main bearing saddles in the block or grinds the crankshafts journals its imperative to double check the work for taper and concentricity with gauges capable of measuring 0.0001".
(3) OEM rods
(A) Install ARP bolts & nuts
(B) Resize the big end
(4) Forged Flat Top pistons TRW (L2379F) or Ross (full round skirts). The round skirts of the Ross pistons spread thrust loads and greatly help to prevent cylinder wall cracking, they are the better choice. They are also designed for thinner rings and wrist pin oiling.
(5) Lightweight steel flywheel (~30 pounds or less)
(6) New crank dampener, a nice fat one (i.e. heavy) like the Boss 351 damper. Steel hub & steel ring, fully bonded. An ATI damper or a BHJ Dynamics damper are both really good choices. The Romac damper is not fully bonded but it is a good damper and a bit less expensive.
(7) Dynamic balance the reciprocating assembly (not the same as internal balancing)
(8) New top quality, hand fitted rings (Hastings, Total Seal, Speed Pro)
(9) Clevite 77 main & rod bearings
>The 351C does not have a defective cooling system. Its cooling system was advanced for its day, and it requires a specific high-flow thermostat to operate properly. That thermostat was unusual for its day, it was not designed the same as the thermostat used in any other American V8. That’s where the problem lies, as most parts counters supply a Windsor thermostat to 351C customers, which is the wrong thermostat.
(10) A Robertshaw 333-180 thermostat (Summit #BRA-333-180) is the correct OEM thermostat. Install no other thermostat in your 351C.
(11) Flow Kooler coolant pump increases flow at low rpm, a good idea for a Pantera. Stewart Components stage 4 351W racing coolant pump can be modified to fit the 351C and offers 4 times higher flow capacity (its rated to flow 160 gpm!).
(12) Rubber rear crankshaft seal (OEM seal was made of rope). Remove the small pointed pin in the seal groove of the #5 main bearing cap.
_______________________________________________________________
Cleveland Lubrication 101
(1) Install Moroso #22050 oil restrictor kit for all 5 cam bearings (0.060”) this requires two kits to achieve enough small restrictors. Do not use the larger restrictor in the left side lifter oil passage. The restrictor for cam bearing #1 requires "special" installation. It is not installed in the same manner as the other 4, if it were it would limit oil to the #1 main bearing. It must be installed deeper within the oil passage.
(2) Install a new standard volume oil pump, Melling #M84A, NAPA #601-1024. The standard 351C oil pump is actually a high volume oil pump, it has a taller rotor than the oil pumps in other Ford V8s. However, if you're not going to install tappet bore bushings a high volume pump "may" improve crank bearing lubrication. I wrote "may" because many lubrication system modifications are fuzzy and theoretical, whereas installing the tappet bore bushings is a "sure" thing.
(3) Fully grooved main bearings (requires using the upper shells from two bearing sets).
(4) Set the bearing clearances properly. Approximately 0.001" clearance per inch of journal diameter. Its usual to run the mains a bit "tight" and the rods a bit "loose" in a 351C.
(5) If you're just going to cruise, never drive your car fast, you can make-do using the factory oil pan. If you are using the factory oil pan, use one with a built-in windage tray, or install an aftermarket windage tray. Cars that are driven fast in corners, accelerated fast, and stopped fast really need a high capacity racing pan with baffles, hinged doors, a windage tray and a scraper. It should be designed to fit in the specific chassis where the motor will be installed & for the intended usage of the vehicle. Pantera oil pan: Armando #404 or Aviaid #155-55365.
(6) Use the high volume oil pump pick-up with the factory oil pan. It was standard equipment in the Boss 351 & 351 Cobra Jet versions. Or use the pick-up provided with the high capacity oil pan.
(7) Install tappet bore bushings to control oil flow to the valve train and improve bearing lubrication. If tappet bore bushings are not installed oil flow to the valve train must be controlled either via oil restricting solid flat tappets, or via push rods with 0.040" restrictors in one tip for hydraulic valve train. Solid roller tappets must use the bushings.
___________________________________________________________
Heads
(1) Select either 1970 (D0AE) or 1971 (D1AE) closed chamber 4V heads. The D0AE heads are best with stock pin height pistons (like the TRW flat tops) and an un-decked block, or for building more dynamic compression with a cam that closes the intake valve later than 70 degrees ABDC. The D1AE head is best with an increased pin height piston (like the Ross pistons) and/or a decked block. The goal for an engine operating on 91 octane pump gas is about 7.6:1 or 7.7:1 dynamic compression.
(2) One piece, single groove, stainless steel valves: Manley Race Master intake and Severe Duty exhaust. Do not use the OEM valves as they have a reputation for dropping the valve heads while the motor is running.
(3) Bronze valve guides
(4) Repair of any recessed valves
(5) Valve springs with about 120 pounds seated force, 330 pounds over the nose (for flat tappet camshafts). Use steel spring cups, titanium spring keepers for the intake valves, chromoly spring keepers for the exhaust valves.
(6) Factory rocker arms & steel fulcrums (4V fulcrums) are OK for hydraulic cams up to about 0.550" net lift. Stronger (ARP) fasteners for the fulcrums are good insurance against "bolt-stretch" because the fulcrum bolts are only 5/16". If you need a better rocker arm, or adjustable valve train consider machining the rocker pedestals and using Yella Terra YT6321 rocker arms. I like the T&D Machine rockers, but they're even more expensive than the Yella Terra rockers. I don't personally use or recommend push-rod guided rocker arms.
(7) Typical Cleveland port work is recommended but not mandatory: this includes bowl clean-up, multi-angle valve seat profiling, exhaust port porting & a bit of valve unshrouding in the combustion chamber. Obviously the more power you expect to make, the more porting such as this will help you achieve your goal.
_________________________________________________________________
Camshaft
(1) Three choices:
(A) Select a Cobra jet camshaft; specs are 270/290 duration, 0.481"/0.490" lift. Set it at 117 degree intake centerline (factory cam) or 115 degree intake centerline (aftermarket replacement).
(B) Ford offered a hotter flat tappet hydraulic camshaft #D1ZZ-6250-BX which was basically a hydraulic tappet version of the Boss 351 cam. It was once a very popular cam, it is available today from a few aftermarket suppliers such as Melling (#24224). The cam specs are 290/290 advertised duration (219/219 @ 0.050), 0.505”/0.505” lift, 114 degree LSA. This cam has 62 degrees overlap, which is about as much overlap as you ever want for a street engine; FYI the 351 Boss camshaft had 58 degrees overlap.
(C) Have a cam custom ground to this spec: 276/286 advertised duration, 112 degree intake centerline, 117 degree exhaust centerline. 52 degrees overlap, exhaust valve opens at 80 degrees BBDC, intake valve closes at 70 degrees ABDC. Net valve lift in the range of 0.550" to 0.600" depending upon the lobes chosen.
(2) Speed Pro HT900 hydraulic flat tappets.
(3) Seamless chrome moly tubing push rods. 3/8 diameter 0.080” wall, or 5/16” diameter 0.116" - 0.120" wall.
(4) Steel timing chain set, 9 keyway crank sprocket. Such as Roll Master #CS3091
(5) Be sure to use motor oil with excellent anti-wear properties, such as Valvoline VR1 10W30 or 20W50
_________________________________________________________________
Ignition
(1) Rebuilt & recurved Duraspark distributor (sourced from a 1977 – 1982 351M, 400 or 460). The MSD distributor with vacuum advance is a good substitute, it uses the same magnetic pick-up as the Ford distributor.
(2) Duraspark I module (sourced from a 1977 – 1979 California vehicle with a 302 V8)
(3) Duraspark I coil. No substitutes.
(4) Duraspark II wiring harness: Painless Wiring #30812, requires a bit of modifying for the Duraspark I module & coil.
____________________________________________________________________
Fuel System
(1) Blue Thunder dual plane intake manifold. This manifold was originally designed by Ford engineers.
(2) Holley style 750 CFM carburetor with annular booster venturis. Plus street-performance calibration and electric choke. I recommend vacuum secondaries, but some guys will prefer mechanical secondaries (double pumper carbs).
(3) Robb Mc Performance #1020 mechanical fuel pump (good for up to 550 BHP). Groovy part, groovy company. "Fat" oil filters hit the fuel pump.
(4) Panteras need to increase the size of the tubing supplying the fuel pump.
______________________________________________________________________
Exhaust
(1) 4V Headers (1-7/8” to 2” primaries)
(2) Low restriction tail pipes (2-1/4" through 2-1/2") and mufflers.
Pantera exhaust: Don't use the OEM Ford Spec exhaust, the European GTS exhaust is a good recommendation. A cam which opens the exhaust valve early helps the engine cope with the small ANSA mufflers.
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From a Strong Performer to a Wild Child
This engine will run forever in this state of tune. It has a mild burble at idle, like any muscle car era factory performance motor did. It has lots of vacuum at idle, peak BHP will be about 365 at 5800 RPM with the Cobra Jet cam, 20 more with the 290/290 hydraulic cam. It has a very enjoyable, street friendly, wide, power band. The limiting factor to this motor's power is the relatively low lift camshaft. Substitute a higher lift (low overlap, wide LSA) custom ground cam and power over 400 bhp is easily attainable with good drivability. This is more than ample power to go fast and push the limits of traction with street tires.
Substitute a solid tappet cam, and matching tappets and valve springs. Increase the size of the carburetor to an 850 Holley; and install a hotter exhaust system and this same build shall make 500 BHP on pump gas. The Holley Strip Dominator intake manifold will return better numbers at peak horsepower and at high rpm, but I don't recommend it for a street engine, and I would personally prefer the mid-range of the dual plane manifold even for circuit racing. With a set-up like this pushing the motor to operate at higher RPM, the 351C turns into a wild child. Better connecting rods are usually part of an engine in this state of tune.
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“A Man’s Gotta Know His Limitations” … Dirty Harry
Enthusiasts competing in drag racing with the 351C get away with making over 600 horsepower without failure of the OEM block or crankshaft; enthusiasts competing in circle track and road course racing with the 351C are not as fortunate however, for that type of competition I recommend setting 500 horsepower & 7000 rpm as your limit if you plan to use OEM block and/or OEM crankshaft. If you want to make more than 500 horsepower I suggest using an aftermarket block with thick cylinder walls and thick bulk heads, an internally balanced and fully counter-weighted steel crank, and better connecting rods.
quote:Ignition
Duraspark distributor
Duraspark I module
George,
Which Duraspark distributor fits the 351C? Part number?
Thanks,
John
The 351C, 351M, 400, 429 and 460 all use the same distributor, in fact the 351W uses the same distributor too, but it has a different drive gear pinned on its shaft. DuraSpark distributors for the 351C are most readily sourced from any 1977 through 1982 Ford vehicle equipped with a 351M, 400 or 460 cubic inch V8.
Thanks George. Is there some way I can bookmark this post so I can come back to it and print it out when I am ready to have the engine guy do the work?
You can always bookmark the page in your browser (CTRL-D), but the problem I've found is that when the forum is updated, categories changed, and threads moved, your bookmark becomes obsolete and doesn't work.
Now, I copy the important content to a Word doc, and also copy the page URL into the same Word doc. That way, if things move, I still have the critical info I wanted to save.
Now, I copy the important content to a Word doc, and also copy the page URL into the same Word doc. That way, if things move, I still have the critical info I wanted to save.
quote:Now, I copy the important content to a Word doc, and also copy the page URL into the same Word doc. That way, if things move, I still have the critical info I wanted to save.
That's my ploy too, if I don't capture information there and then all too often I can't find it again.
Julian