One thing that all engines respond to even with a big cam is write the firing order down on paper or a card. Split them in half, first four above the last four. Then look at the card to see which cylinder you want to adjust. When one cylinder on the list comes up on overlap (equal exh and int opening pressure on the springs) then go to the opposite cylinder and adjust. I know this sounds confusing. It does insure the base side of the cam of the cylinder is where you need to be for adjustment. Everyone I have told this to gets that deer in the head lights look, but once you do one cylinder, it gets clear.