[madmaxx]

Why not turn your engine over until both valve closed then EASILY apply air pressure to the cylinder via a spark plug hole adapter and it will force the piston all the way down at this point do your leak down test, the engine will no longer rotate. I did this while changing valve springs and it worked much easier then finding top dead center on each cylinder. The engine will rotate very slowly if you apply the pressure slowly, you apply the pressure quickly and it will slam over. Make sure it is out of gear so you dont run over your foot.