This reminds me of an issue I had 40 years ago in my 4 speed days. I was lucky enough to have a crank in my 340 that had the smaller hole but the bushing slid in and out. After trying a few backwoods mechanic tricks a buddy of mine finally machined me a very nice bushing. Seeing a broken bearing retainer on the floor he also made me up one in stainless steel instead of the stock cast iron. Silly question here but did he ever do mods to his suspension and if so did he double check his pinion angle. I swear standard transmission cars seem more critical to this.