['ol Pinion head]

The 28 spline 8.5 posi carriers with #8 & #9 cast into the ends of them are for c-clip axles but can be used in bolt-in axle 8.5 rears & that's where most of the ones I reclaimed have ended up being used.

One thing George doesn't note in his article, is the claim rate for used S spring 8.5 posi's with good clutches. I started pulling these in the late 80's & have literally pulled & built rears with hundreds of these carriers. In the 8.5 posi carriers I've pulled in the last 15 years, a good 80% I've torn down needed all new clutches. Most of these posi's were out of low horse 70's & 80's big cars, not like they all came out of thrashed TransAms & Z28's. When I first started buying the GM clutch kits for these I paid little over $48 a box. Last ones I bought were over $122 a box. Several dealers were over $170 a box. Good luck finding any now, as GM discontinued them close to two years ago. I've heard Ratech was going to reproduce (read source) these posi clutches, but nothing from them so far. Without a source for new clutches, the used carriers are a gamble at best.

Another non serviceable part is the side gears, GM discontinued these over a decade ago & they were very expensive. I always robbed side gears out of the high ratio #9 carriers, then shimmed up the side gears with an assortment of side gear shims, some I had to have made.