Most of time the pilot bushing gets very little wear. The only time the main shaft moves in the pilot bushing is when the clutch is disengaged. Any other time the main shaft and the crank shaft are locked together. By the clutch. The concerns about the main shaft to pilot bushing can be addressed with a few measurements. Measure the shaft diameter at the end on both transmissions. They should be the same plus or minus a few thousandths. If they are you are good for this part. Measure from the mounting surface to the "step" at the end of the main shaft and to the end of the main shaft. On both transmissions. If these are the same it will fit. The bushing can be removed and replaced if it is worn. You can run a tap into the bushing and then install a bolt. You then pull the bolt and bushing out. Or you can fill the bushing with grease and put a bolt that will slide into the bushing part way in, then hit that bolt with a hammer. Hydraulic pressure from the grease will push the bushing out. Clean it up and put a new bushing in. The pilot bushing does two things. 1, supports the long main shaft. 2, protects the crankshaft from wear.
