Gentlemen,
I have a new 377 stroker Cleveland that isn't making all the HP I expected. The chassis dyno showed 326 HP at 5650 rpm. Torque was 325 lbs at 4000 rpm. I am running 10 to 1 compression ratio with the closed chamber 4V cast iron heads. I went with a Comp Cams Hydraulic roller cam part #32-541-8. Duration numbers are 290/290 and 230/230. Lift is 578/578 and lobe separation is 110. The cam is supposed to be good from 2500-6000 rpm. I am using Isky #8005-A valve springs. Lifters were part of Comp Cams K-kit for this cam. The intake manifold is the Edelbrock Performer which is only rated to 5500 rpm. I have the Mind Train headers and exhaust. The engine made HP up to 5650 rpm, after that, HP and torque dropped like a stone! By the time we got to 5800 rpm, we only had 265 HP. There was a problem on the primary side of the carb which made the front two idle mixture screws ineffective. It turns out it was a blown power valve that has since been repaired. The power valve repair made no seat of the pants difference in performance, which is what I expected. I could take the car back to the dyno and see if they can get any more horses out of it but I suspect there is not a lot more they can do? I am guessing the intake is my problem. I've heard of guys making power all the way to 6400 rpm with the Performer, but maybe due to the extra cubic inches, the Performer is choking my air flow enough to not allow any more rpm? I don't want to go to a high rise manifold because I want to keep the engine screen on the car. I have modified the mounts for the screen to allow another half inch of clearance. I am thinking about the Blue Thunder manifold designed for the Pantera and sold by Dennis Quella. What do you guys think?
Thanks,
Art
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