How much horsepower can l31 vortec heads with the stock ports yield? I'm going to be running the cc306 cam 230/244 duration, .510/.540 lift; intake/exhaust. Compression will be exactly 10.2:1. I'm Aiming for 420hp at the flywheel. I've see plenty of LT1 guys claiming 360ish RWHP with stock heads, boltons, and this cam. The lt1 heads flow very similar to the vortecs.

Here are a couple of examples.

http://www.popularhotrodding.com/eng...ock/index.html

http://www.carcraft.com/techarticles...ine/index.html