Ok, there's no way in hell you can be on that OR stay on that straight through turning the engine. You need this, and you need to make a piston stop. Real easy. Piece of 2x4 the width of the deck. Bolt it on with two head bolts. Drill a hole in the middle and put a bolt and nut in it and tighten it down. Then bolt that on the deck.
Proform Cam Checker Tools 66843