I have a set of 346236 Peanut Port Oval heads. 120cc 225/116cc ports. I don't know anything about the internals of my motor. I know that they peanut ports are the worst head for performance, so if I were to find a head with the same size chambers, possibley a little smaller, and bolted them on with a little polishing and porting, would I see any performance gain? Or would I only see a differnce if I changed around the cam (Unknown specs) to get mor lift/duration. Just looking for a little more? So are there any con's to doing this, other then the dent in the wallet? I am looking for GM Iron heads. Any good numbers to look for?

Thanks a lot,
Chris

You won't see any improvement unless you turn the engine fast enough to need more airflow. Yeah, that "probably" means new cam 'n' springs.

I put on a set of Gen 6 Vortec heads, (easy swap) and gained about 200 rpm on the top end, but the heads I took off were pretty worn-out. The Vortec heads are not known for great intake flow, unlike their smallblock cousins.