500hp & 600hp Bench Racing thread

273 said
Yes I don't have a dyno and not discounting your professional experience but I'm not basing my thoughts out of thin air either and not saying it's the same as your experience but I got make do with info available to me, but I going on 40 years of poring over and comparing every engine build I've seen. Why I'm trying to understand but I need a theory to base it on not cause "we say so", There must be a theory what's holding the smaller displacement back since we know the top end is capable of the hp?

More CID by definition means more stroke or more bore. BOTH of those equate to greater generation of forces. Overcoming that with RPM requires a different cam for the little guy.

Years and years and years of testing more less show that part-swapping really only 'tilts' the HP curve (top end goes up, bottom end goes down, etc). There needs to be a change in engine efficiency (cylinder head flow and QUALITY of flow, ring packages, rod ratio, etc) to shift the curve straight up. But if you shift it, the same thing will happen to the bigger motor with the same changes. Changing most of these things also tends to cost more than swapping a cam or headers.

So, in a nutshell, generating power with RPM means giving up low-end or fabricating bespoke parts. In a racecar, the rpm trade can be worth it since the car will live full-time above 5k. But the same changes to induction can be made to the bigger motor to also spin faster... a die grinder is cheap and quickly takes all the slow out of the ports - just don't grind the fast out of them.