Rebuilt 318 Refuses to Start

If you crank the engine over with your finger in no 1 spark plug hole, you'll hardly be able to hold your finger in against the air pressure. There are two piston strokes that push air out, compression and exhaust strokes. So if you hold your finger in for 5 or 6 revolutions, you'll know what I'm talking about. You want the one that pushes the most air out, that is the compression stroke. On the exhaust stroke, the exhaust valve is open, also, and bleeds off most of the air pressure so it pushes less against your finger.