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Cleveland Horsepower Wanted

G Guest
First off, I have to say that I don't own a Pantera, but I do own a 351C powered Shelby Cobra replica.

It seems to me that the Pantera owners are the experts on the Cleveland, so I am hoping you can help me.

My engine is a '72 CJ, with open chamber 4V heads. It has an Edelbrock Performer 351-4V intake, a Holley mech sec 700 DP with 70 primary jets and 78 secondaries. The cam has 220 duration at .050 on both intake and exhaust, with .505 lift. The previous owner installed restrictor plates on the intake side, but the exhaust side plates are in the trunk of the car. Header tubes are 2 inch diameter. Timing is set at 16 initial and 36 total. After a recent tuneup, it was chassis dyno'd wih results of 233 hp and 287 torque.

It seems like there should be more streetable power available, I'm just not sure where, nor what mods have the best return for the dollar.

I'm not prepared to go with the Aussie heads nor IR EFI (yet), so I am looking for carb or timing adjustments; cam, intake or carb replacement suggestions, or other ideas.

Your input would be much appreciated.

Thanks,

Keith
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OA old and slow (Guest)
Keith,
You might want to check an earlier post "First time on a dyno". You did not state what your compression ratio was, or if a compression check was done. How many miles since a competent rebuild. Certainly closed chanber heads might help as well as a more aggressive cam. What kind of headers are you running etc., etc. I'm sure you will get a number of responses from very knowlegable people on this web page. Hang in there, there is a lot of things you can do, but the best results probably will come from the proper selection of compatible parts.
Lar
72 Pre-L 3663
RT Rolling Thunder (Guest)
The engine was professionally rebuilt approx. 18K miles ago (1987). I have owned the car about a year. A compression check has not been done, but I believe it to be in the 9.0 - 9.5:1 range based on the reference books I have. It has flat top pistons and a 30 overbore. As for headers, being a Cobra, the down tubes exit laterally to the side of the car, coming together in a collector for the side pipes which terminate ahead of the rear wheels. There is some muffling occuring, but not much. Let me know what other info would be of assistence - I'll provide what I can.

Thanks,

Keith
X XLR8R (Guest)
Has anyone dynoed their car before and after the port plates? I am in the same boat as rolling thunder, similar parts, intake plates, exhaust plates in my garage. I did not notice much/any improvement when I installed the intake port plates, but I have no dyno #s. I still beleive the 1 7/8 exhaust diameter would be keeping the rear wheel HP below 300 on these clevelands, no matter what mods you have.(on the Panteras) Thanks, Carter
rmccallrmccallMember
I don't think the primary tube size is as restrictive on alot of Pantera headers as alot of the collector size .I had a set of "Big Bore"headers on my car and the collector wasn't even 2".I think the collector and the tailpipes have to be atleast 2 1/2" to be effective.
Rolling Thunder:I think your car would benefit from more compression and camshaft.I run flat tops with closed chamber heads and a camshaft with .550" lift and 235/240deg @.050.I also run a Blue Thunder intake .My car made 340 hp at the wheels with a 750 DP and no tuning.I have Hall 180 headers with 2 1/2"Flowmaster mufflers.I don't think they make any more HP than a good set of aftermarket headers but they sound and look AWESOME!I did see a noticable gain with the Blue Thunder intake over the Edelbrock I switched from.Hope this helps.
Q qwkgt5 (Guest)
Just my two cents.Clevlands love split duration cams.You want more exh. duration to make up for the little exh. valves.Also dont forget to use putty to check valve to piston clearance if you have more than 550' of lift.I have run many a clevland and love the bang for the buck with those sweet big port heads(just dont expect low end but have gobs of hp over 3000 rpm!
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