Perhaps in my case, but the numbers on heads are the same, but not in Cab's case, he already had decent heads and still only went 2/10ths faster with much better ally heads, perhaps if he had upped the CR by 2pts it would've gone quicker?...........Also didn't the Indy 440-C iron head make as much if not more power than the -1 if I remember well with equal porting.