307 vs 308 bearing retainer

I've not done this, but it makes sense. Get a 4.80 diameter retainer that'll fit your bearing, either size. Or get a machine shop to turn your OD retainer down to the 4.80 size. and then enlarge the hole in your aluminum bell to fit. Or use the aftermarket bell, they come with the 4.80 sized hole. Let us know what you do!