Okay, I haven't measure to check interference, but the bearing to crankcase is definitely an interference fit. It seems like it is the same scenario as more modern saws, which I haven't seen this setup. Not trying to say that the engineers didn't know what they were doing, but I know there has been a learning curve (650 with two needle roller bearing, belt drives with needle bearing on the FW side and ball bearing on pto side, for examples). In the end, I have crossed all of the bearings in all models of big homelites to modern part numbers- except one- the 750 pto bearing. That Torrington DD series bearing is unique it seems