Before diving into the details of this 8.2-inch 10 diff build, we figure we should address a couple of questions that are sure to pop up. First of all, the 8.2-inch 10-bolt rearend came in a Chevy and B-O-P (Buick-Olds-Pontiac) versions; for our purposes that means it was found in '62-67 Chevy II/Novas, and also various Novas, Chevelles, and El Caminos through the '72 model year. Question two, which follows quickly and more vehemently, is, "Why would you build one of these things?" So we'll explain the why, and also what we did to make this thing a viable dragstrip diff.
The why of this story follows the idea that it's cheaper to build up what you already have than to buy something else. Would a 12-bolt or a 9-inch be stronger? Absolutely, but a full, new replacement setup for our subject '67 Nova would cost at least $2,000. We did find a few used 8.5-inch 10-bolts and 12-bolts during some online searching, but not many-and they were of indeterminate quality. Someone looking to make this swap with used parts would have to factor in the costs of a rebuild and retrofit in addition to whatever was paid for the core diff.
Dave Stoker had all this in mind when it came time to rehab the rearend in his 11-second '67 Nova, a car that gives off no external evidence of its dragstrip prowess. When it comes to cost, Stoker tells us that a core 8.2-inch 10-bolt fetches about $150, if not less, on the open market. Stoker certainly had cost considerations in mind, but he was also looking to keep a Nova rearend in his Nova, as well as maintain its sleeper persona-right down to its bantamweight diff.
Ironically, the diff that needed replacing was the victim of a faulty posi unit, not the small-size differential itself. With this in mind, our first move was to raid the Eaton catalog for PN 19603-010, which is a Limited Slip Differential for '64-72 Chevrolet 8.2-inch 10-bolts with 28-spline axles and 3.08-or-steeper gears. Obviously, we wanted both wheels a-turnin'. On the other hand, Eaton posi units comes filled with forged gears and carbon friction dics, which will handle the 11-second abuse we'd be throwing at it.
Our second call was to Randy's Ring & Pinion. If you call Randy's for tech support, you'll probably be talking to Terry Burg, as we did. In short, we looked to upgrade every piece we could. The Yukon Gear ring-and-pinion set we chose (in the Nova's original 3.36:1 ratio) is made to be stronger than OEM gears while running as quietly as a stock set. The 1541H steel axles we chose are 25 percent stronger than OEM pieces, according to Randy's. We also ordered a Master Rebuild Kit, which comes with Timken bearings to ensure strength and durability.
Our first order of business,...
Our first order of business, of course, was to disassemble the 8.2-inch 10-bolt donor rearend that we would rebuild for dragstrip duty in Dave Stoker's intrepid '67 Nova. This original open carrier wasn't too bad off, but the bearings did show wear and pitting. The cross-shaft was hammered-Rick Galloway had to drive it out with a punch, unlike the C-clips, which just fell out of place. Except for the C-clips and the carrier shims, this assembly is off to the junk pile.
With the axles and ring carrier...
With the axles and ring carrier removed, Galloway proceeded to the pinion yoke. If you don't have a puller, he suggests removing the yoke using an air hammer with a point, rather than a hammer and punch, to avoid damaging the pinion assembly. If you're not reusing the pinion, this is less important. We weren't looking for unnecessary carnage, so we did it the clean way.