[jim_howard_pdx]

What is happening is that the oil pump drive is either leaning against the side wall of the distributor opening or the internal hex is not aligning with the pump shaft.

NO WORRIES

Simply seat the distributor as far as you can, and applying light pressure on the top cap have someone bump the starter. As the engine rotates the cam engagement will turn the distributor shaft until it picks up the oil pump shaft and the distributor will seat.

NEVER pound down on the thing. Just bump the engine.

Hope this helps.

Jim