In a engine like this you gonna make around 1.7-1.9 hp per cfm, so eg. 240 vs 300 cfm = 408-456 hp vs 510-570 hp with appropriate cam intake exhaust etc.. Including CR so say 10.5:1 for these power numbers vs 7.5:1 is about 10% hp loss on so 40-60 hp power loss on some of these numbers. Worst case on your eg. the lowest 300 cfm - 60 hp basically ties the highest 240 cfm with high cr. But this is an extreme cr difference, generally your talking a a lot less. But in some cases the loss of cr can lose more than the gain flow depends on the numbers were talking about. But general the hp gain of good amount of additional cfm is gonna be a net positive even at the sacrifice of a point or so of cr.