Join Date: Nov 2006
Location: Toms River, New Jersey
Re: Max HP through stock exhaust manifolds SBC
As to a recommendation....hmmm. I would think that the manifolds would prefer a lower rpm torquer than a high rpm big breather type of motor. Say a Lunati flat tappet hydraulic cam(230/230 @0.050, 0.455/0.455-inch, 144 degree lobe seperation) with a fresh set of iron vortec heads(with the adapters so you can use earlier style valve covers). Factory Z-28 intake manifold, holley 750 vacuum secondary with dogleg or annular boosters, 9.5:1 d-dish forged or hyper pistons on 5.7 factory rods. It may seem to be a bit tame, but in a 406 based motor the combo was good for 427 hp at 5100 and 525ft/lbs at 3500 and was putting out over 450ft/lbs from 2200-5000rpm(according to BIG-INCH CHEVY SMALL BLOCKS by Graham Hansen's "406ci Torque Monster" example). Granted the 406 was using an air-gap intake instead of the z-28 manifold and 1 5/8 headers rather than cast iron manifolds and 23 extra cubes, but you should be able to reach say within 20% of those numbers. Thats not bad at all. It wouldn't be a very expensive build either. Just an idea.