Join Date: Jan 2015
Location: Injun Territory, 'Merica!
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Looks like an early 8.2 BUICK 10 bolt to me. I have one out of a '64 442 post car. Also in the racks, have a '68 BUiCK 8.2 10 bolt out of a '68 GS400. Both have pronounced castings where the plug welds go to attach the axle tubes. That stated, the 68-70 Buick 8.2 10 housing has diagonal ribs & much more "beef" in it's housing.
Buick built their own cast hag 8.2 10 bolts for '64-66 Buick Specials. Olds also used the BUICK 8.2 10 bolts for all '64 Olds F-85's, late intro '64 442's, & most '65 & 66 F-85's & 442's. Eventually Olds engineers realized the single rib design of the cast center secton was weak, & they specified gray iron Pontiac 8.2 10 bolts for the 400-4spd '66 442's. Some Pontiac 8.2 10 bolts were also used in late '65 442's. The gray iron 8.2 Pontiac center section used a twin converging rib design on each side of the front of the center housing. The twin converging rib design continued its use for both gray iron & nodular housing PONTIAC 8.2 10 bolts through the '72 model Pontiac A body's.
Warranty concerns eventually precluded the gray iron 8.2 center housings use under '67 Pontiac A body's with 3.55, 3.90, & 4.33 Safe-T-Track, as Pontiac engineers specified nodular iron 8.2 Pontiac center housings for '67 8.2 A body Safe-T-Track rears with the aforementioned ratios.
Oldsmobile introduced their "Type O" Olds 10 bolt rear during the '67 model run. These rears are often mistakenly referred to as "Olds 12 bolts" due to their 12 bolt smooth cover. Under the cover is an 8.3" 10 bolt carrier, they are 10 bolt rears.. The Type "O" housing & rebuildable clutch type posi carrier were a major improvement over the previous early8.2 BUICK design, but the most common Type "O"s was not that much of an improvement over earlier offerings & like all gray iron 8.2 10 bolts lacked serious pinion support.
Buick for their '68 model A-bidys totally redesigned their 8.2 10 bolt. These had a '68-70 BUICK 10 bolt specific housing, specific 4 pinion posi carriers, specific (different pitch) 28 spline axles, as well as their own specific ring & pinion sets.
With all the major difference's, this is why a very experienced GM differential builder does not use such terms as "BOP 10 bolt", I cringe nearly every time I read that uninformed term.
Last edited by Pinion head; 04-07-2017 at 06:46 PM.