I've seen the 8.5" 10 bolt talked about with "small" axle shafts (I believe these are 1.28" diameter) and "big" axle shafts. My understanding is that in '88 a 30-spline 10-bolt was introduced, that in '92 and later models all (GM trucks) had 30-spline "big" axle shafts, but that from '88-'91 there were some "small" and "big" axle shafts, some with 28-spline and some with 30-splines (Chevy & GMC Pickup Performance Handbook).
My (stupid) questions are as follows:
1. I've seen the "big" axle shaft listed as 1.30", 1.31", and 1.32". Are these three distinct axle shafts, different part numbers? Some sources pointing to my '95 2DR 4WD Tahoe having 1.32" shafts.
2. Were all "small" 1.28" axle shafts "necked down" 1/8" at splines at the differential end?
3. Were any "big" axle shafts "necked down" at the splines at the differential end?