New engine/low HP

I'm no expert, but from all the other postings that I've seen over time the Performer intake is probably choking your engine. I have a Blue Thunder intake and all fit under the screen (barely) when I was running it.

Art, one thing you might try that is relatively inexpensive is maybe a differant air cleaner?? I know the air has to make some sharp turns before it can head down the carb and if there isn't a lot of room between your air horns and the top of the air cleaner, it acts like a restriction. I heard thos dog bone ones are actually pretty good.

Hi Art,

2511 runs a .030 over Cleveland, Performer, Holley 670, a dropped Moroso cleaner that makes the air work to get down the carb throat, and the big Ansa GTS headers/mufflers. My cam is very mild compared to yours, but my chassis dyno had HP climbing to 292 at about 6150 until it dropped off like a rock.

What size is that Big Bore choking your exhaust down to? Primaries?

Sounds like air flow issues - intake/exhaust/both?

Larry

Art the intake's gotta go... some of the other biys can give you a recommendation but thats a street intake. I have a torker you can try and it fits under the screen with a Moroso air cleaner brand new black. Both are for sale.

The power valve which did you select .. if I remember correctly you need a vacumn guage and what ever vacumn you have at idle you need 1 point higher or lower. its been a while maybe some one can clarify that. Jetting .. you need a selection of jets DYNO day.

Keep trying the HP will come up.

Ron

Art,
What did they end up chargeing for those pulls,I was thinking of taking mine over to dyno. or better yet lets get a dyno day going.
My 1/2 cent: ditch the intake and open the headers.

Art,

the dyno is the best place to diagnose a problem. I have more questions than answers at this point.

First, my random observations. Your motor is making about 407 bhp at the flywheel, which is about all you're going to make using the cast iron 4V heads without porting & a good valve job (multi angle). Although the cam is rated for power out to 6000 rpm by Comp Cams, thats with a 351 cubic inch motor, the extra displacement of your stroker moves the power band lower in rpm, I would have guessed power to 5750 rpm, but 5650 is close enough. David Berman had his motor dyno tested with an Edelbrock Performer adapted to work with his Blue Thunder heads, that motor made a tad more than 500 bhp, at around 6000 rpm, feeding a 408 cubic inches. I never liked the Performer myself, but David's dyno results has given me a new found appreciation of that intake, you can make more power at the upper rpm with other intakes for sure, but I do not believe the intake is what is "choking" your motor. It may very well be the characteristics of that cam to drop off like a brick above the powerband, rather than the torque curve tapering downward at a slower rate, which is why sports car guys normally want a wide flat torque curve, rather than an upward tilted one. The upward tilted ones drop off faster beyond peak torque. When all is said and done, you may very well need a custom ground cam to get the characterisitcs you want.

Having written all that, I myself would not be satisfied with the performance of your motor either. I would expect it to perform better too.

OK, here's my questions:

Do you have assurance that the person who built your short block did a good job with the rings as far as getting them to seal well in the cylinders?

Did the dyno operators run any air/fuel ratio numbers while your motor was on their dyno? If so, what were the numbers like between 4000 & 6000 rpm?

What components is your ignition composed of, and how old are they?

What is your ignition timing specs?

What parts are your fuel delivery system composed of & how old are they?

What make & size is your carburetor?

What are you using for an air filter and was it installed during dyno testing?

What size are the exhaust pipes of the mind train system, and what type mufflers does it use?

Have your heads been ported and had a multi angle valve job?

How do the specs of the Isky 8005A springs compare to the springs recommended by Comp Cams?

your friend on the DTBB

Thank You Dennis,
Art

quote:

Originally posted by 4NFORD:
I'm no expert, but from all the other postings that I've seen over time the Performer intake is probably choking your engine. I have a Blue Thunder intake and all fit under the screen (barely) when I was running it.

I am using a 3-1/2" tall round K+N filter. When I had the carb worked on this week, I had them mill off the choke horn in anticipation of squeezing a taller manifold under the screen. Milling the choke horn gave me no seat of the pants improvement. So, I don't think the air filter is holding me back?
Thanks,
Art

quote:

Originally posted by DeTom:
Art, one thing you might try that is relatively inexpensive is maybe a differant air cleaner?? I know the air has to make some sharp turns before it can head down the carb and if there isn't a lot of room between your air horns and the top of the air cleaner, it acts like a restriction. I heard thos dog bone ones are actually pretty good.

Larry,
The primaries (header tubes) are 2" OD which I guess makes them 1-7/8's. The exhaust pipe from the headers to the four glass packs is about 2-1/4" OD so I guess you would call it 2-1/8".
Thanks,
Art

quote:

Originally posted by LF - TP 2511:
Hi Art,

2511 runs a .030 over Cleveland, Performer, Holley 670, a dropped Moroso cleaner that makes the air work to get down the carb throat, and the big Ansa GTS headers/mufflers. My cam is very mild compared to yours, but my chassis dyno had HP climbing to 292 at about 6150 until it dropped off like a rock.

What size is that Big Bore choking your exhaust down to? Primaries?

Sounds like air flow issues - intake/exhaust/both?

Larry

Ron,
I don't know which power valve they installed. I also did not realize a Torker manifold would fit under the screen. Is that the later screen with the raised sheet metal section?
Thanks,
Art

quote:

Originally posted by accobra:
Art the intake's gotta go... some of the other biys can give you a recommendation but thats a street intake. I have a torker you can try and it fits under the screen with a Moroso air cleaner brand new black. Both are for sale.

The power valve which did you select .. if I remember correctly you need a vacumn guage and what ever vacumn you have at idle you need 1 point higher or lower. its been a while maybe some one can clarify that. Jetting .. you need a selection of jets DYNO day.

Keep trying the HP will come up.

Ron

Dennis,
They charged me $150 the first time which was just a diagnosis with no dyno pull. They charged me $130 the second visit which included three or four pulls? Their regular price is $180 with no changing of jets, $300 or $310 if they change jets. A dyno day would be cool!
Thanks,
Art

quote:

Originally posted by daleyracing:
Art,
What did they end up chargeing for those pulls,I was thinking of taking mine over to dyno. or better yet lets get a dyno day going.
My 1/2 cent: ditch the intake and open the headers.

Dennis,
Do you have the same cam as I do, the Comp Cams #32-541-8 hydraulic roller? If so, what kind of rpm's can you turn? It sounds like your engine screams!
Art

quote:

Originally posted by daleyracing:
Art,
What did they end up chargeing for those pulls,I was thinking of taking mine over to dyno. or better yet lets get a dyno day going.
My 1/2 cent: ditch the intake and open the headers.

George,
Russ Fulp built my engine, he has also built engines for Dennis Antennucci, Dennis Daley and Matt Meritt. Russ has a very good reputation. As for rings seating in the cylinders, I don't know? A problem started early on with excessive oil consumption, like a quart every 200 miles. That turned out to be bad intake gaskets (Mr. Gasket) that I replaced with Fel-Pro's. I'm not sure that has completely solved the oil consumtion problem, I suspect there is a little blow by going on. Russ says he sets his engines up loose, but I'm not sure my rings seated properly? The dyno guys gave me no air/fuel info. My ignition includes a new msd 6-al box with a 6500 rev limiting chip. The distributor is a Ford, Duraspark? The coil is an Accel Super Stock #8140C, a typical looking cylindrical unit. The coil is seven years old with about 18,000 miles on it. The distributor was in the car when I bought it in 1997, I've put about 30,000 miles on the car and distributor. The guys at the dyno shop set the timing to 34 degrees total, I noticed they plugged my vacuum advance, it is still plugged. I have all new fuel lines and filter. I have a new mechanical fuel pump that is supposed to be good for 120 gph. It is an Allstar brand #40263. The dyno guys watched my fuel pressure gauge during the pull and they said pressure never dropped below 6 psi. I have a Holley 750 double pumper with mechanical secondaries. I believe it is a 4150/4779. It was set up by Jet Performance for my new engine. I am using a 3.5" tall round K+N part #E-1540 air filter. The air filter was in place during the dyno test. The headers appear to have 1-7/8 inch primary tubes with 2-1/4 O.D. exhaust pipes running into four glass packs. The heads were not ported, but Russ did a multi angle valve job on them. I haven't found the specs for the Isky or the Comp Cams springs. I guess I should ask Russ why he chose to go with the Iskys. I hope you are wrong about the cam, (that intake sure would be a lot easier to change), but you seem to be very knowledgeable about this stuff.
Thank you very much for your help,
Art

quote:

Originally posted by george pence:
Art,

the dyno is the best place to diagnose a problem. I have more questions than answers at this point.

First, my random observations. Your motor is making about 407 bhp at the flywheel, which is about all you're going to make using the cast iron 4V heads without porting & a good valve job (multi angle). Although the cam is rated for power out to 6000 rpm by Comp Cams, thats with a 351 cubic inch motor, the extra displacement of your stroker moves the power band lower in rpm, I would have guessed power to 5750 rpm, but 5650 is close enough. David Berman had his motor dyno tested with an Edelbrock Performer adapted to work with his Blue Thunder heads, that motor made a tad more than 500 bhp, at around 6000 rpm, feeding a 408 cubic inches. I never liked the Performer myself, but David's dyno results has given me a new found appreciation of that intake, you can make more power at the upper rpm with other intakes for sure, but I do not believe the intake is what is "choking" your motor. It may very well be the characteristics of that cam to drop off like a brick above the powerband, rather than the torque curve tapering downward at a slower rate, which is why sports car guys normally want a wide flat torque curve, rather than an upward tilted one. The upward tilted ones drop off faster beyond peak torque. When all is said and done, you may very well need a custom ground cam to get the characterisitcs you want.

Having written all that, I myself would not be satisfied with the performance of your motor either. I would expect it to perform better too.

OK, here's my questions:

Do you have assurance that the person who built your short block did a good job with the rings as far as getting them to seal well in the cylinders?

Did the dyno operators run any air/fuel ratio numbers while your motor was on their dyno? If so, what were the numbers like between 4000 & 6000 rpm?

What components is your ignition composed of, and how old are they?

What is your ignition timing specs?

What parts are your fuel delivery system composed of & how old are they?

What make & size is your carburetor?

What are you using for an air filter and was it installed during dyno testing?

What size are the exhaust pipes of the mind train system, and what type mufflers does it use?

Have your heads been ported and had a multi angle valve job?

How do the specs of the Isky 8005A springs compare to the springs recommended by Comp Cams?

your friend on the DTBB

Art,

Thanks for providing the info, sorry for the third degree.

have you spoken to Russ about this? I know who Russ is because other Pantera owners like Dennis A speak very highly of him. I would expect him to have built you a top notch motor, and am surprised to read you're having trouble with it knowing he's the builder. There's a mechanics code of honor by the way, one mechanic doesn't criticize or second guess the work of another, at least not publicly, ahem.... Mechanics are all a very highly opinionated bunch, become irritated easily. If we went around second guessing each other, we'd end up throwing burning carburetors through each others windows in the middle of the night. You've never heard of a "Holley-tof cocktail"?

Shame on your dyno operators for not taking A/F ratio readings! That would have provided you with very critical info (1) you have an air/fuel problem, or (2) you don't have an air/fuel problem. At least you would know to concentrate on other areas.

I wish your problem could be solved as easily as with a manifold swap too. You can always borrow one from somebody & give it a try, but I wouldn't go out & buy one until after I tested the theory with a borrowed manifold. If we lived closer I'd let you borrow my Holley Strip Dominator. Surely one of the OC guys has a torker you can borrow.

We are talking about 2 "possibly" unrelated issues, so lets make that clear, (1) your motor is not producing the power that we expect from it (2) your motors torque curve drops like a brick above 5650 rpm. Your peak torque, at 4000 rpm, is not what I would expect, which is why I say the issues "may" be unrelated.

Regarding issue #1, ring seal is very important, if they don't seal properly, then you'll never achieve the bhp numbers you are expecting. On the other hand, Russ is quite capable of building a good short block, so I would lean towards ruling that issue out. If fixing problem #2 doesn't resolve problem #1, a leak down test may be called for. I can also guarantee you that your heads need some porting to achieve the numbers you and I both expect for your motor. The exhaust port demands most, but not all, of the attention. The roof of the exhaust ports has a bump that needs removal, and a flat surface that requires blending out to the exhaust flange. The whole exhaust port (sides, floor) also needs to be blended and "straightened out" dimensionally. I would also like to see at least 2 1/2" tubing between the collectors and the mufflers. I have no experience with the mind train exhaust system, if it will support more than 400 bhp or not. I like the Magne Flo muffler, like those sold by PI Motorsports, better than the dual glass pack systems I've seen. But liking something, and having actual dyno experience with it, are 2 completely different things.

Regarding issue #2, while a single plane intake WILL make bigger bhp numbers for you, I don't expect the Performer intake manifold to affect the motor the way you desribe, i.e. the drastic drop in torque above 5600 rpm. It will roll the curve off, but not that drastically. Thats more of a symptom I would expect from a fuel problem, an ignition problem, or a camshaft design issue. I'm just not familiar with the Comp retro-fit roller cam, so I am unable to say if that's normal for that cam or not. Dennis A's engine has the next size bigger Comp Cam and pulls to the mid 6000 range just fine. He's running C302 heads of course.

I've had engines exhibit similar charactersitics before, once it turned out to be a lifter had partially come apart, the push rod was still in place, it wasn't making any noise, but the guts of the lifter were laying in the lifter valley, that lifter wasn't opening it's valve! That one busted my balls for several days. More common was the old Holley running too rich syndrome. A rich carb will make the motor drop off like that. I've seen a 351C that wouldn't rev beyond 4800 rpm for that reason. But I wouldn't expect that from your "tuner" carb.

I would also not discount the older ignition coil, performance of coils does taper off with age & use, and aftermarket parts quite often do not have the longevity of oem parts. The MSD box could have a defect also. Ohming the spark plug wires would also be a good idea, especially the wire between the coil & distributor. You may want to monitor the voltage supply to the coil or ignition box while its being run on the dyno, the Pantera electrical system may simply just be dropping the voltage to the coil or MSD box as the current draw increases. A method to diagnose that issue is to install a direct jumper between the battery & ignition using a heavy gage (12 gage) length of wire with alligator clips on both ends. Ignition issues are also something that can be easily diagnosed on a dyno with an engine analyzer.

One test you can run is to rev the motor in the driveway & determine if the motor hits a brick wall under those conditions (unloaded) or only on the dyno.

It's getting late Art, I'm running out of steam. I hope I've given you some ideas. Perhaps some of the other guys have ideas.

Your friend on the DTBB

Art,

Taking my daily look through eBay, I see there's a Torker on right now, finishing in less than 12 hrs and still at under $70 (for now at least).

At that price you could take the chance and resell it if its not for you.

http://cgi.ebay.com/ebaymotors/351-Cleveland-Edelbrock-...QQrdZ1QQcmdZViewItem

> David Berman had his motor dyno tested with an Edelbrock Performer adapted to
> work with his Blue Thunder heads, that motor made a tad more than 500 bhp, at
> around 6000 rpm, feeding a 408 cubic inches.

He'd gain a bunch by moving to a Yates intake.

> Your motor is making about 407 bhp at the flywheel, which is about all you're
> going to make using the cast iron 4V heads without porting & a good valve job
> (multi angle).

Dan Haynes made right at 500 HP on unported 4V heads on a high compression
351C. He'd have made more with porting but the heads are not the limiting
factor here.

> The primaries (header tubes) are 2" OD which I guess makes them 1-7/8's.
> The exhaust pipe from the headers to the four glass packs is about 2-1/4" OD
> so I guess you would call it 2-1/8". exhaust pipes running into four glass
> packs.

The primary diameter is too large, the collector too short and the exhaust
pipe too small. If your mufflers are too restricitive (and glass packs are
often among the worst), you won't see much benefit from header tuning.
Some exhaust system rules of thumb:

OID = SQRT (Ex_CFM * 1.27/FD)
CD = 1.75 * OID

where:

OID = optimal internal diamter (inches)
Ex_CFM = exhaust port flow (CFM) at 28" H20
FD = flow density (around 80 CFM/square inch @ 28" H20)
CD = collector diameter (inches)

Primary lengths between 24 to 36 inches (for bank separated 4-into-1
on V8's with dual plane crankshafts)
collector length between 12 and 20 inches good for 8000 RPM

Mufflers should flow 2.2+ CFM per HP (the point at which there is a 1%
difference between mufflers and open pipes), 500 HP requires two 550 CFM
mufflers

A friend tested his unported 351C-4V heads (Super Flow at 28" water, in CFM,
stock single-angle valve job and 5/16" Manley valves with an MPG port plate)
and at your peak lift, they were around 180 CFM without a pipe. Plug in the
numbers:

OID = SQRT (180 *1.27/80) = 1.69 inches
CD = 1.75 * 1.69 = 2.958

Most Pantera headers have collectors way too short (5 or 6 inches) with
too small ID collectors and exhaust pipes and way too restrictive mufflers.

> I am using Isky #8005-A valve springs. Lifters were part of Comp Cams K-kit
> for this cam.

Comps K-Kit includes the springs and lifters. For some reason you're engine
builder chose not to use the K-kit springs. Comps standard hydraulic roller
lifters don't rev well. The Crane link-bar lifters have proven to rev much
better and Comp has recently introduced their version of a link bar lifter
but I've not seen any test data on those. Much care must be exercise in
picking the springs and lifters when trying to get a hydraulic roller cam
to rev well with heavy 4V valves and 1.73:1 rocker ratios.

> Your motor is making about 407 bhp at the flywheel,
> I have a Holley 750 double pumper with mechanical secondaries.

In addition to the Performer intake being a wrong choice for your set-up, your
carb is a limiting factor. 100 HP requires 140 CFM based upon a reasonable
assumption for Brake Specific Fuel Consumption (BSFC). The BFSC assumption
keeps us from having to guess at volumetric efficiency. A 407 hp engine uses
an actual 569.8 CFM. 4 barrel carbs are rated at 1.5" Hg but that is way too
restricitive on a tuned engine. 0.7" Hg is a more reasonable pressure drop
(too keep the carb from being a limiting factor). Converting to rated carb
CFM:

Flow @ 0.7 In Hg = (CFM Rating @ 1.5 In Hg)/SQRT(1.5/0.7)
569.8 = X / 1.46385
X = 834 CFM flow rating required

> I'd let you borrow my Holley Strip Dominator. Surely one of the OC guys has a
> torker you can borrow.

I offered up a Strip Dominator, Blue
Thunder, Boss 351, and Torker for a dyno test but I don't think he's interested.

But what about PI?

Art,
I basically have the same cam as Dennis A's but the seporation is for webers lift is 613.
and my 180's are 2" with 3.5 collectors. and 11:1 cr
so I need to get mine to the dyno.
Thanks
Dennis D

Dan what about step tube headers?
I always thought that an 850 DP Holley was the best "Performance" carb out of the box. It is ok on the street but a 750 is crisper.

> But what about PI?

What about PI?

> Dan what about step tube headers?

They can approximate a tapered header well enough. First step same as the
port outplet size, last step the size required by the formula. This stuff
is best optimized by something like Dynomation.

> I always thought that an 850 DP Holley was the best "Performance" carb out of
> the box. It is ok on the street but a 750 is crisper.

Best depends highly what it's going on but the HP series and Demon carbs
flow more these days for the same venturi area.

Dan Jones

quote:

Originally posted by Daniel_Jones:
> But what about PI?

What about PI?

Well I thought you would never ask. I'd like some Apple Pi a la mode thank you.

Dan Jones

quote:

Originally posted by Daniel_Jones:
...He'd gain a bunch by moving to a Yates intake....

David's engine builder dyno'd the motor with both intakes, I don't have the figures before me, but the Yates intake made something like 40 bhp more above 5000 rpm. David did indeed elect to run the Yates intake. For every extra bhp the Yates intake made above 5000 rpm, the motor lost an equal amount below 5000 rpm. I would have selected the Performer personally. You probably know that about me by now.

quote:

Originally posted by Daniel_Jones:
...your carb is a limiting factor. ... X = 834 CFM flow rating required....

Good point Dan, I glossed right over the carb last night. I have witnessed the 750 Holley take motors into the 500 bhp range, and the HP series, which weren't around 20 years ago, will do even better. But I can't argue that you can probably bolt 40 bhp on by going to an 850 HP carb, especially on a 377 stroker motor. On the street I would advise Art to run the smaller carb. Isn't Dennis A runnng a 750?

quote:

Originally posted by Daniel_Jones:
...I offered up a Strip Dominator, Blue
Thunder, Boss 351, and Torker for a dyno test but I don't think he's interested.

From the "aluminum containmant facility"! Show off! LOL......

Dan, you're the man! Your friend on the DTBB

Here is one more little bit of info regarding my car: I think one of my four glass packs is bad based on the sound. I can see most of the way thru all the glass packs and I see no obvious obstructions. It seems like a long shot, but could this be the problem or part of it?
Art

Yes.

You could be choking off 4 cylinders.

It would be like stuffing part of a potato in someones tail pipe. Not enough to kill the motor, but enough to limit how high it revs.

George

Thank you George,
Can any of you folks recommend some new mufflers that will flow well? Are there any to stay away from? The mufflers PI has for sale do look nice. I'm sure my neighbors would be ecstatic about new mufflers.
Art

quote:

Originally posted by george pence:
Yes.

You could be choking off 4 cylinders.

It would be like stuffing part of a potato in someones tail pipe. Not enough to kill the motor, but enough to limit how high it revs.

George

Thank you again Dan for all the good information,
Art

quote:

Originally posted by Daniel_Jones:
> David Berman had his motor dyno tested with an Edelbrock Performer adapted to
> work with his Blue Thunder heads, that motor made a tad more than 500 bhp, at
> around 6000 rpm, feeding a 408 cubic inches.

He'd gain a bunch by moving to a Yates intake.

> Your motor is making about 407 bhp at the flywheel, which is about all you're
> going to make using the cast iron 4V heads without porting & a good valve job
> (multi angle).

Dan Haynes made right at 500 HP on unported 4V heads on a high compression
351C. He'd have made more with porting but the heads are not the limiting
factor here.

> The primaries (header tubes) are 2" OD which I guess makes them 1-7/8's.
> The exhaust pipe from the headers to the four glass packs is about 2-1/4" OD
> so I guess you would call it 2-1/8". exhaust pipes running into four glass
> packs.

The primary diameter is too large, the collector too short and the exhaust
pipe too small. If your mufflers are too restricitive (and glass packs are
often among the worst), you won't see much benefit from header tuning.
Some exhaust system rules of thumb:

OID = SQRT (Ex_CFM * 1.27/FD)
CD = 1.75 * OID

where:

OID = optimal internal diamter (inches)
Ex_CFM = exhaust port flow (CFM) at 28" H20
FD = flow density (around 80 CFM/square inch @ 28" H20)
CD = collector diameter (inches)

Primary lengths between 24 to 36 inches (for bank separated 4-into-1
on V8's with dual plane crankshafts)
collector length between 12 and 20 inches good for 8000 RPM

Mufflers should flow 2.2+ CFM per HP (the point at which there is a 1%
difference between mufflers and open pipes), 500 HP requires two 550 CFM
mufflers

A friend tested his unported 351C-4V heads (Super Flow at 28" water, in CFM,
stock single-angle valve job and 5/16" Manley valves with an MPG port plate)
and at your peak lift, they were around 180 CFM without a pipe. Plug in the
numbers:

OID = SQRT (180 *1.27/80) = 1.69 inches
CD = 1.75 * 1.69 = 2.958

Most Pantera headers have collectors way too short (5 or 6 inches) with
too small ID collectors and exhaust pipes and way too restrictive mufflers.

> I am using Isky #8005-A valve springs. Lifters were part of Comp Cams K-kit
> for this cam.

Comps K-Kit includes the springs and lifters. For some reason you're engine
builder chose not to use the K-kit springs. Comps standard hydraulic roller
lifters don't rev well. The Crane link-bar lifters have proven to rev much
better and Comp has recently introduced their version of a link bar lifter
but I've not seen any test data on those. Much care must be exercise in
picking the springs and lifters when trying to get a hydraulic roller cam
to rev well with heavy 4V valves and 1.73:1 rocker ratios.

> Your motor is making about 407 bhp at the flywheel,
> I have a Holley 750 double pumper with mechanical secondaries.

In addition to the Performer intake being a wrong choice for your set-up, your
carb is a limiting factor. 100 HP requires 140 CFM based upon a reasonable
assumption for Brake Specific Fuel Consumption (BSFC). The BFSC assumption
keeps us from having to guess at volumetric efficiency. A 407 hp engine uses
an actual 569.8 CFM. 4 barrel carbs are rated at 1.5" Hg but that is way too
restricitive on a tuned engine. 0.7" Hg is a more reasonable pressure drop
(too keep the carb from being a limiting factor). Converting to rated carb
CFM:

Flow @ 0.7 In Hg = (CFM Rating @ 1.5 In Hg)/SQRT(1.5/0.7)
569.8 = X / 1.46385
X = 834 CFM flow rating required

> I'd let you borrow my Holley Strip Dominator. Surely one of the OC guys has a
> torker you can borrow.

I offered up a Strip Dominator, Blue
Thunder, Boss 351, and Torker for a dyno test but I don't think he's interested.

Thanks Dennis, I suspect we'll see some pretty good numbers from your engine.
Art

quote:

Originally posted by daleyracing:
Art,
I basically have the same cam as Dennis A's but the seporation is for webers lift is 613.
and my 180's are 2" with 3.5 collectors. and 11:1 cr
so I need to get mine to the dyno.
Thanks
Dennis D

George and friends,
Dennis Antennucci is running an 850 cfm carb. I would have thought that when I took my carb in to have it set up for the new stroker engine, they would do what was necessary to make it work well. I've heard of smaller carbs set up to flow like larger carbs, it didn't even dawn on me that I might not have enough carb to get the job done. When you mention another 40 HP from an 850, that sounds good. I just figured my carb would be correct for my application when I got it back from the carb shop. At this point, could I possibly gain 40 horses by switching to an 850?
Art

quote:

Originally posted by george pence:

quote:

Originally posted by Daniel_Jones:
...He'd gain a bunch by moving to a Yates intake....

David's engine builder dyno'd the motor with both intakes, I don't have the figures before me, but the Yates intake made something like 40 bhp more above 5000 rpm. David did indeed elect to run the Yates intake. For every extra bhp the Yates intake made above 5000 rpm, the motor lost an equal amount below 5000 rpm. I would have selected the Performer personally. You probably know that about me by now.

quote:

Originally posted by Daniel_Jones:
...your carb is a limiting factor. ... X = 834 CFM flow rating required....

Good point Dan, I glossed right over the carb last night. I have witnessed the 750 Holley take motors into the 500 bhp range, and the HP series, which weren't around 20 years ago, will do even better. But I can't argue that you can probably bolt 40 bhp on by going to an 850 HP carb, especially on a 377 stroker motor. On the street I would advise Art to run the smaller carb. Isn't Dennis A runnng a 750?

quote:

Originally posted by Daniel_Jones:
...I offered up a Strip Dominator, Blue
Thunder, Boss 351, and Torker for a dyno test but I don't think he's interested.

From the "aluminum containmant facility"! Show off! LOL......

Dan, you're the man! Your friend on the DTBB

I think the game plan should be to "fix" whatever is wrong with the motor now, i.e. the sharp fall off in power. Afterwards you can go on the hunt for more bhp. To do otherwise will not provide you the results you're expecting. If you indeed have an exhaust blockage, fixing that could very well boost the power numbers to were you expect them, with no further changes what so ever.

Your friend on the DTBB

Sounds like good advice George, thank you,
Art

quote:

Originally posted by george pence:
I think the game plan should be to "fix" whatever is wrong with the motor now, i.e. the sharp fall off in power. Afterwards you can go on the hunt for more bhp. To do otherwise will not provide you the results you're expecting. If you indeed have an exhaust blockage, fixing that could very well boost the power numbers to were you expect them, with no further changes what so ever.

Your friend on the DTBB

> But what about PI?

Ahh, you meant Pi :-) I forgot about that post and totally missed your
meaning. I saw PI and thought Pantera International and drew a deer in
the headlights blank stare :-)

> David's engine builder dyno'd the motor with both intakes, I don't have
> the figures before me, but the Yates intake made something like 40 bhp
> more above 5000 rpm. David did indeed elect to run the Yates intake.
> For every extra bhp the Yates intake made above 5000 rpm, the motor lost
> an equal amount below 5000 rpm.

Do you recall which Yates intake he used? Some don't work well out of
the box and need plenum work. I suspect they are designed that way to
permit custom work to allow them to be used on restrictor plate engines.
Also, a carb optimized for the Yates intake with annular boosters might
have been able to close the gap on the low end. Some of these tuner carbs
are pretty good these days but they have to be matched to the combo.
Sometimes the annular boosters help a bunch sometimes they hurt. It's a
completely differen type of carb but just to show the influence a carb can
have, I loaned a Strip Dominator to a buddy once to test a Predator (a.k.a.
Kendig) variable venturi carb once. With the variable venturi carb, the
big port Strip Dominator was better from idle on up than a much worked on
Offy Dual Port with spreadbore carb combo optimized for low and mid-range.
The Predator was able to meter fuel and low vacuum signals and overcame
the big open plenum of the Strip Dominator.

> I would have selected the Performer personally. You probably know that
> about me by now.

and I would have picked C302B heads with an IR intake :-)

> Good point Dan, I glossed right over the carb last night. I have witnessed
> the 750 Holley take motors into the 500 bhp range, and the HP series, which
> weren't around 20 years ago, will do even better. But I can't argue that you
> can probably bolt 40 bhp on by going to an 850 HP carb, especially on a 377
> stroker motor.

> On the street I would advise Art to run the smaller carb.

I'd rather him run a carb that flows 830+ CFM but meters as well or better
than a standard Holley 750. Proper attention to airflow can yield a carb
that flows more but atomizes better. A friend with a 372C, very similar
cam to the one Art is running (same specs but with XE lobes), and stuffed
4V heads with Parker Funnelweb just borrowed a Demon 750HP (I think he said
it flowed 815 or 830 CFM) and was amazed at how much better it was than his
750 Holley across the board. It was tuned on the dyno and I should be able
to get jets and power valve info should Art choose to go that route.

> Isn't Dennis A runnng a 750?

Dennis is running a tuner carb. I forget the exact specs but it flows quite
a more than 750. I don't have the numbers handy but it was in the range
where it needed to be.

> At this point, could I possibly gain 40 horses by switching to an 850?

I loaned my spare Blue Thunder to a Pantera owner in Kentucky (Jack Butler)
for a dyno test against an Offy 360and an Edelbrock Performer. The engine
was a 377 cube 351C stroker (0.600" solid lifter cam, 108 lobes, 6" rods,
offset ground crank, 10.5:1 compression, Willy's modified 950 HP carb, also
tested his old 650 Holley). Unfortunately, he ran all the tests with MPG
intake port plates, so I think that biases the intake manifold results but
not the carb results. The Offy 360 did very poorly, down 50 HP to the
Edelbrock. While the Offy isn't much of an intake, I think the port plates
hurt the Offy but helped the Performer which has smaller ports that match
more closely to the port plates. The Blue Thunder did best but the margin
between it and the Performer wasn't as large as expected, probably due
to the port plates. I loaned out my binders with the dyno sheets and Jack's
write-up but I believe the combo made a bit under 475 HP. Jack said the
Willy's modified 950 HP carb made a huge difference over the admittedly
undersized Holley 650 DP. IIRC, the carb change was equal to the difference
between the best and worst intakes (over 50 HP). You're starting with a
larger carb so I would think your results wouldn't be as dramatic but there's
power to be had.

> Here is one more little bit of info regarding my car: I think one of my four
> glass packs is bad based on the sound. I can see most of the way thru all the
> glass packs and I see no obvious obstructions. It seems like a long shot, but
> could this be the problem or part of it?

You need to get a look at Vizard's muffler tests. Even though you could
see straight through them, some of the glass packs were terrible when it
came to flow.

> Can any of you folks recommend some new mufflers that will flow well?

Walker flow rates their mufflers now using the Vizard suggested standard
pressure drop. Other manufacturers will tell you the pressure drop if
you call the tech line and ask. Look for Vizard's no loss exhaust article.
I'll see what I can dig up plus I'll ask a co-worker on his muffler dyno
test results. Due to competition, mufflers have come a long way in recent
years and the best ones can rival no muffler at all.

> Are there any to stay away from?

Quite a few, unfortunately. The other thing big cork in the exhaust is
likely your collectors. Most of the off-the-shelf Pantera headers lack
a meaningful collector and headers are much more sensitive to collectors
than primary pipe lengths. I bought my headers uncoated so I could
hack off the collector and put a proper one on.

Dan Jones

Dan did you ever test the Ford D1ZX single plane Doninator manifold?

You guys know more than I do... I remember the old saying.."If you can make it breath you can make it RUN" I run a 850 cfm on 409 ci so you are going to need somthing close to that for your stroker.

quote:

Originally posted by Daniel_Jones:
...I'd rather him run a carb that flows 830+ CFM but meters as well or better than a standard Holley 750. Proper attention to airflow can yield a carb that flows more but atomizes better...

You know me, I'll always opt for driveability when there's a choice to be made. But I agree Dan, if the new carb tuners can take the big carb and tune it so there are no compromises in drivability, then by all means, that's the way to go. In fact, that's BITCHEN!

> Dan did you ever test the Ford D1ZX single plane Doninator manifold?

No but that one looks very similat to a Weiand Xcelerator 4V.
I'd expect it's operating range to be similar to the Weiand
Xcelerator 4V.

Dan

Is that a scientifically accurate statement?

Dan,
You have mentioned the Blue Thunder high rise intake as being a possible solution to my problem. What do you think about the the Blue Thunder designed to fit under the screen of the Pantera, If you give it the green light, I'll probably just order the damn thing and move on.
Thanks,
Art

quote:

Originally posted by Daniel_Jones:
I loaned my spare Blue Thunder to a Pantera owner in Kentucky (Jack Butler)
for a dyno test against an Offy 360and an Edelbrock Performer. The engine
was a 377 cube 351C stroker (0.600" solid lifter cam, 108 lobes, 6" rods,
offset ground crank, 10.5:1 compression, Willy's modified 950 HP carb, also
tested his old 650 Holley). Unfortunately, he ran all the tests with MPG
intake port plates, so I think that biases the intake manifold results but
not the carb results. The Offy 360 did very poorly, down 50 HP to the
Edelbrock. While the Offy isn't much of an intake, I think the port plates
hurt the Offy but helped the Performer which has smaller ports that match
more closely to the port plates. The Blue Thunder did best but the margin
between it and the Performer wasn't as large as expected, probably due
to the port plates. I loaned out my binders with the dyno sheets and Jack's
write-up but I believe the combo made a bit under 475 HP. Jack said the
Willy's modified 950 HP carb made a huge difference over the admittedly
undersized Holley 650 DP. IIRC, the carb change was equal to the difference
between the best and worst intakes (over 50 HP). You're starting with a
larger carb so I would think your results wouldn't be as dramatic but there's
power to be had.

> Here is one more little bit of info regarding my car: I think one of my four
> glass packs is bad based on the sound. I can see most of the way thru all the
> glass packs and I see no obvious obstructions. It seems like a long shot, but
> could this be the problem or part of it?

You need to get a look at Vizard's muffler tests. Even though you could
see straight through them, some of the glass packs were terrible when it
came to flow.

> Can any of you folks recommend some new mufflers that will flow well?

Walker flow rates their mufflers now using the Vizard suggested standard
pressure drop. Other manufacturers will tell you the pressure drop if
you call the tech line and ask. Look for Vizard's no loss exhaust article.
I'll see what I can dig up plus I'll ask a co-worker on his muffler dyno
test results. Due to competition, mufflers have come a long way in recent
years and the best ones can rival no muffler at all.

> Are there any to stay away from?

Quite a few, unfortunately. The other thing big cork in the exhaust is
likely your collectors. Most of the off-the-shelf Pantera headers lack
a meaningful collector and headers are much more sensitive to collectors
than primary pipe lengths. I bought my headers uncoated so I could
hack off the collector and put a proper one on.

Dan Jones

Art I know that you are asking Dan and I don't mean to butt in, but T.S. I ran the Shelby version of that manifold. The Blue Thunder is a copy and "improved".
I found it to a restrictive manifold and made me want my Edelbrock Torker back.
I never blamed the intake for being flat under 4200. I always felt those were the iron 4v head characteristics.
If you deport the torker (like the one I have for sale) you make the engine noticably more responsive from around 3000rpm and up instead of 4000 to 4200 and up.
The Torker is a race manifold that is streetable.
It needs "gears" to run right.
If your local town decides to bring back trollies and needs grooves cut for the tracks, they will hire you to do it if you run the Torker. (Bet ya' don't know no trollies huh?)

Jerry Brubaker got his to fit below the engine screen, Blue Thunder, 14" round air filter, Corvette dropped air filter base, Edelbrock carb. It looked tight, but it was below the screen.

The Blue Thunder is available in a "flat mount" carb base version for cars in which the engine sits flat, like the Pantera. The Blue Thunder carb pad is very close to the same height as the Holley Strip Dommy.

Art, I like the BT intake a bunch, but with what Dan has written about the new crop of "tuner" carbs being able to make the open plenum intakes work as good as the 2 plane intakes, I would think the Holley Strip Dommy & a tuner carb would make the "best" combo.

To give you an idea how these things stack up in my mind, in the '70s & '80s I installed the BT intake with hydraulic cams, with power bands roughly in the 2000 to 6000 range. The Holley Strip Dommy intake was mated with solid lifter cams with power bands in the 3000 to 7000 range.

The Holley Strip Dommy & BT intakes are in my opinion the 2 best intakes for the cast iron 4V heads. They have the same carb pad heights, and will cost you about the same money ($300 to $350). One emphasizes the low end a bit more, one emphasizes the top end. But like everything else in the 21st Century, sounds like automotive technology has blurred the old lines.

Just please keep in mind, you have a problem to resolve with the motor dropping off like a ton of bricks at 5600 rpm that either intake is not going to fix.

your friend on the DTBB