The crank register is the part that extends out from the crank flange that the hole in the middle of the flywheel fits over, it centers the flywheel onto the crank some were 2-3/4 inch dia. some were smaller. The catalogue the napa guy used stated the flywheels would fit all years and sizes of engines which just isn't so, and he wouldn't know any different.
The hole drilled into the end of the crank is what the pilot bearing fits into. As far as I know the pilot bearing holes were all the same size to fit the 1.387 inch outside diameter pilot bearing which is close to 1-3/8 inch. Some of the later automatic tranny engines did not have the pilot bearing hole drilled. You stated earlier you needed a new brass ring that the bearing was pressed into maybe someone drilled the pilot hole oversize then put in a bushing to reduce the size of the hole to fit the bearing. Just guessing here.
