Just a reference comment....
Doesn't everyone remember back when hopping up muscle cars, that someone would put all these goodies into their car... cam,heads,headers,intake,exchaust... and the car ran slower?
And conversely, there was always a guy who would run all the "stock" parts or maybe all GM parts and his car would be stunningly fast?
And then there is Winston Cup, 355 cu in, Low CR, w/o restrictors, 8700 rpm and 850 HP, and....
Busch, 355 cu in, 9:1 CR, restrictors plates, ~480 cfm 4bbl and 535 HP.....
Consider the Winston engine, you could add 2 cyl (increase by 25%) to get 445 and decrease rpm 20% to 6960 rpm to get the same 850 HP.
And contrary to a lot of belief, changing displacement does not effect peak HP. Peak HP is basically an indication of the flow potential of the induction system. When you increase displacement, you merely reduce the rpm that peak HP occurs at.
This is why a bigger engine needs a bigger cam to make bigger HP.
The key to HP is the cylinder heads and the intake.