340 4 speed crank

There's a good chance you're crank has allready been drilled by the factory, but just not finish drilled. in which case you can get an undersize pilot bearing bushing.
If it's not drilled at all, you can also cut off an inch or so from the tip of the input shaft, and put a later style bearing in the crank, where the hub of the converter goes in.

Antoon