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Old 05-10-2011, 12:55 PM
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cobalt327 cobalt327 is offline
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From another thread:

Quote:
A couple months ago, Car Craft did a test of a Demon Engines crate BBC 4-bolt 454 +0.030" (461 ci), Peanut Port heads (118cc chambers = 9.4:1 CR, stock valve sizes) w/a XE 268H Comp cam (.515"/.520" lift, 224/230 @0.050" duration on a 110 LSA), w/a Holley HP 750 carb and a (too-large) set of 2.25" headers.

It made 446 HP @ 4900 RPM/542 TQ @ 3600 RPM. 490 ft/lbs @ 2500 RPM. There's no doubt the numbers would've been better w/a smaller primary header diameter, IMO.

So, the PP heads are low RPM torquers, for sure. But not total dogs.

That said, the same engine, using a Edelbrock RPM Air Gap intake, Holley 950 HP carb, Comp XE284H cam and a set of Profiler 290cc aluminum heads made 564 HP @ 6100 RPM and 542 TQ @ 4900 RPM.

That's a gain of 118 HP over the smaller cam and heads. The 950 HP Holley doesn't flow anywhere near 950 CFM (said to flow less than a standard Holley 850) and the two intakes are basically the same as well (changed for a better port shape match), so the difference was mostly just the heads and cam.
Using a cam smaller than the 284 w/the 781 heads and a dual plane RPM-type intake and correct sized headers will get you there. The heads should be at least pocket ported and larger valves will help the peaks.
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