Slightly strange head flow question.

The cam has .540 lift with 1.5 rockers? If it's a 59* SB you won't see that lift at the valve unless you run 1.6 rockers because of bad pushrod/lifter angles.

300 cfm at .600 lift doesn't mean much if you only poking the valve .500-.540. and realizing/accessing flow numbers around .500 at best.