Finding top dead center is easy, look at the harmonic balancer. Rotate the engine with the #1 spark plug removed to 0,you should feel or hear the compression, if none rotate around again to 0 the compression stroke. remove the distributor cap and see where the rotor is pointing. It should be pointing to #1 . If you didn't replace the oil pump drive in correctly it could be off causing starting problem . If the rotor is not pointing at #1 remove the distributor and look at the position of the distributor slot in the oil pump drive . The slot must be facing straight front to back of the engine. if not use a long screw driver to rotate the drive to the proper direction, [ rotate the drive not the engine ] then replace the distributor, The rotor should now be pointing to #1.