I went from a .650 lift flat tappet to a more aggressive roller but also went from 12.5 to 14:1 compression at the same time. Went from low 9.80's to low 9.60's.

67 Coronet 500 9.610 @ 139.20 mph
67 Coronet 500 (street car) 14.82 @ 94 mph
69 GTX (clone) - build in progress......