we have a timing lite mounted on a stand,that runs during dyno pulls.i have found it is comon to gain or lose timing at the top end of the pulls. not realy sure why? last hei with advance lock out would retard 2 to 3 in the last 500rpm of the pull. slack in the timing chain, distributor shaft end play, gear wear, cam walk. all might contribute some, and lets not forget the control module. i like solid cam thrust buttons. roller bearing types have seized up, and the needle bearings have gotten through moroso oil pick tubes :cry: had good luck with cloyes covers, some times they dont get along with stock type water pumps. hope this helps stickboy331