318 horsepower

I was told that the 302 heads are the ones to have on a 318 due to the smaller combustion chambers and ports making better flow and more compression without changing pistons or milling heads, etc. What advantage would a Magnum head give you? I'm not saying they don't,and I am not by any means an authority, but what would the advantage be, and wouldn't the magnum heads lower his compression? Mike

P.S. If you decide to switch heads let me know, I'm looking for a set of 302s.