That is very accurate. An engine with a small cam, and less head, would care much less what intake was on it. one over 450 HP....they tend to care more :p
We have a very small cam TBI 87-95 SBC engine that works with stock EFI of the era. We can build that engine with GM dumper 87-95 small valve heads, OR...we can throw our aluminum 2.02 valve heads that we use up to 500HP on everything else. both engines will make the same HP, because the cam is so mild...it simply can't use the head flow.
