I went from a 440 to a 512 stroker. The results were dramatic!! Granted we upped the compression 3 points went with a bigger roller and went with Pro-Comp heads (unported) We rolled the ring and pinion back from 4:56s to 4:10s Same car 73 Cuda (3550 lbs with driver) same carb, headers. Car went from a best of 11:90@112mph To 10:40@130 and we're still sorting it out.....