Take your time and install the trans WITHOUT any clutch components. Take a rod or other item and a straightedge so you can accurately measure the depth from the bell flange to the pilot cavity bottom, then compare that to the shaft length of the trans
An Un finished (automatic) crank may NOT be deep enough. The cure is two possibilities
Cut a bit off the shaft, or have the crank finished. The more modern "Jeep" style pilot, which fits into the converter register, seem to be a better deal than trying to fit the factory type bushing into an undersized hole (You can buy undersized bushings)
Newer, "Jeep" style comes in bushing or roller bearing: