If you need more shim under the pinion for proper set up ,could you just add the needed shim under the brg race instead ? Seems to me it would work with out any ill affects . 8.5 GM 71-72 year Thanks ick
Best bet is to grind center of a good used bearing,then you can swap shims quickly .Early Dana's set up with shim behind race,probably work with no I'll effects,but generally harder to find larger shims.My shop builds average of three diffs per week I can prob help with whatever you may need.Good luck.