Join Date: Jan 2015
Location: Injun Territory, 'Merica!
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'64 Pontiac A-bodys had the small upper control arm mount and the Pontiac 8.2 10 bolt gray iron cast center hsg should have casting #9773369. This particular housing is easily spotted by the casting number and the small cast mounts for upper control arm bushings. Buick also cast a small upper control arm mount '64 8.2 rear, but the early Buick 8.2 has it's own style casting and own casting number.
The next chronological Pontiac 8.2 10 bolt was cast 9773722, then there was the 9779822. All 3 of these Pontiac gray iron casting numbers one can find on the early (narrow) style Pontiac 8.2 10 bolts.
The 9788647 center hsg Pontiac 8.2 rear you have is a nodular iron housing Pontiac 8.2 10 bolt out of a '67 Pontiac A body. Most likely from a GTO, and factory assembled with 3.55 gearing and the 4 pinion Safe-t-track carrier. Much stronger rear than the original gray iron 8.2 10 bolt, but 1" wider, has the larger upper control arm bushings, and should have the fluted locator style coil spring mounts, not the '64-66 style that use the clamp on style coil spring attachment.
No 8.5 A body rears till '71 model, and even then not factory installed in Pontiacs. As a long time GM differential builder, and having helped popularlize the performance 8.5 A body build, have built many 8.5 A body rears for '64-66 A bodys. Have also had several customers that were into disquising these later HD 10 bolts to look just like earlier Pontiac 8.2 10 bolts.
Last edited by Pinion head; 08-23-2015 at 04:18 PM.