BORE SHROUDING TEST: 4.03" vs 3.91" Edelbrock RPM Heads Really Fit a 318? Project Mission Impossible

66fs said
You guys need to just build stuff. Dyno's and theoretical stuff can or can not help. A guy I know was racing dirt track with a 318 and 340 X heads, had the fastest car on the track. That test is questionable at best. My experience is the same as 318willrun, 340/360 heads with any either 1.88 or 2.02 intake valves takes a 318 to the 340 level. I always had the heads milled .040 and .038 intake side to keep the compression the same or better. Of course you also need the cam, valve springs, intake, carb, and distributor.

All it is, is a piece of information, outside of the 15-25 cfm loss across most the lift range it tells us little in itself, how an engine will respond from this loss ? To me 400 hp and under probably very little looking at how sub 400 hp 318 perform. But at some point it probably does have an effect. But since most aren't building 500/600+ hp 318 most will probably never be overly effected.