The volume of air the engine ingests is the same for [a] the cyl capacity & [ b] the rpm.
A 400 Chev that is turning 4531 rpm ingests the same volume of air as a 400 Chrys turning 4531 rpm....around 500 cfm. Doesn't matter what the CR is or how big the cam is...it is the same.
CFM [ cubic feet per minute ]. It is a volume measurement. Not weight or density.
What changes is the air density, & therefore the mass of air ingested into the engine. More mass, more HP.
