Get the OD of the crank and the input shaft. Replace the bushing with a good sealed bearing. I did this on my 68 Barracuda over 25 years ago, it was in the car when I sold it and the now owner says he's put three clutches in the car and is still using the same bearing.
The engine I have is drilled for the "true" 4-speed bushing. Are you saying use the "auto crank" style of adapter bearing, and leave out the bushing? Either way, thank you very much for the input.