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head wise, how can a stock type head make that kind (450-500) of power? 915 & 906 Mopar heads just do flow what a good stock small valved small block chevy head flows. I can see where the monstrous torque comes from but how can they feed a 6,000-6,500 rpm 500-550 HP 440?





I realize you love mopars too, so don't take any offense to anything I mention, but I notice a lot of GM guys look at BB mopar heads, and can't believe we get any power out of them. I had a friend call mine "tractor heads" After he put twin screws on his 454 it was finally faster than my car, but that's a different story.

I guess the only answer to how is it that they perform, is that a motor isn't a flow bench.

500 hp out of an iron headed big block with very minor port work is not tough. Especially if you go with a 440 or bigger.

My 915's are still stock valve size. Port work is/was minor. I do agree with john rr's comment that you can make it worse too.

Just remember you're not trying to redesign the head, just smooth it out a little.