I got the 455 in the machine shop this week, 500 HP build. Goin with my TH400. Tell me, my car has the stock 10 bolt, open, 2.76 gears. Should I go with a build-up, or wait till it blows up and go looking for a 12 bolt. I noticed that lots of you guys run 10 bolts with girdles and beefed-up internals, but my dads logic always has been that 100 bolts were too weak to even waste your time on. Can they live? Is it worth the money. And what would you recommend. Thanks, Jon
A well-built 8.5" 10 bolt will survive just fine. I'm sure others with direct experience will chime in. If you're running the 8.2" 10-bolt, time for an upgrade. Devon
Well built 8.5 A-body 10 bolt rear is the way to go, until one really spends the coin on custom tapered bearing bolt in axle 12 bolt w/ 33 spline HD Eaton carrier, there is no advantage going with the 12 bolt. Your '68 should have a '68-70 BUICK 8.2 rear. The '68-70 BUICK 8.2 is very hard to find good low ratio gears & posi's for, and on the '68's & 69's one still has sealed axle bearings, which often need to be replaced For more info on HD built 8.5 A-body rears, do a search here in Got Gears. Got Posi? :3gears: Roger
It'll be fine for now but if you plan on gettin a little crazy,a set of new axles(28 spline is ok if thy're aftermarket ones) and a new posi should last behind that motor for a long time.You're gonna need some more gear in there also to utilize that new power correctly:Brow: .
Don't understand that response, for the avg enthusiast who has a '68-70 BUICK 8.2 in his/her ride, there is very little reason to spend $$$ on the '68-70 BUICK 8.2 rearend. High point restorations, SURE, going to the trouble chasing near extinct parts, & spending the coin makes sense, but anything else HP Street or Street/Strip, $$$ is better spent on the much superior 8.5. Again to reitterate: -There are no new posi's for the '68-70 Buick 8.2, have to search & search & search for a good used original posi carrier. Expect $450-550 expense on such a low ratio carrier in decent shape. -New Moser axles for a '68-70 Buick 8.2 with new bearings installed. & axle studs will run close to $400 when delivered. -More gear... no new '68-70 BUICK 8.2 gears. Result... hunt & hunt , & roll the dice on used when one finally finds a set of used BUICK 3.42's or 3.64's. -Less pinion support with the BUICK 8.2 vs an 8.5. The 8.5 can be built to withstand much higher torque loads. Got Posi? :3gears: Roger
No problem Jeff. In response to the original poster, not all GM 10 bolts are alike, as the '60's rolled along nearly each GM division built stronger & stronger versions of some form of 10 bolt rear. Chevy, as the exception, stayed with one of the weakest designs, the 8.2 c-clip 10 bolt, in auto's with under 295 hp. Got Posi? :3gears: Roger
Exactly why I just sold my 70 3.42 OO coded 8.2.. I am heading toward the 8.5 with a 30 spline Eaton carrier,30 spline axles and 3.90 gear ratio..I am getting what I want and need and so is Chris who bought my rearend. We are both happy and got the rears we need for our cars..
I'm new to all this diff. stuff, so maybe i'm wrong on this or don't understand how the R&P work... Eaton makes a posi for th 70' 8.2 10 bolt, Summitracing part# ETN-19674-010. Auburn does also. drivetrainspecialists.com has gears, So does Motive Gear Performance. 3.55 to 4.56
That is because there were years that were just BOP 8.2 rears. These were pre 68 models. The 68-70 Buick 8.2 is a different creature and I believe is Buick specific. The confusion lies in the fact that the pre 68 rears and the 68-70 rear share the same diameter ring gear dimension of 8.2 inches. So the figure "8.2 " appears in both sets so people assume they are they same rears but they are not.
So does that mean the following Eaton posi would not fit in a Buick 8.2 rear? 19674-010 GM BOP:1964-1971 10 8.20 28 T 3.08 & Up
I am not the one to answer that on . Ask Roger (OPH.) There has always been a lot of controversy over this issue.
as far as 8.5 goes, youll be fine with good parts, for awhile. you start running a good slick, my problem in my chevies[ had a COUPLE] is the stock axle on the right side kept snapping.wnet with strange axles, no probs. did a lot of street racing when i was younger, alot of trial and error. if your just running streets, you will be fine.
Below is a tech sheet link to a friend in Dallas's '66 LeMans. Extremely well thought out combo, & has run a blueprinted 28 spline S spring 8.5 posi & stock axles with slicks for many years. At Floyd's LeMans' performance level, in all performance 8.5 builds, I tend to err on the safe side & upgrade to the HD Eaton carrier & 30 spline Mosers. With what rustfree sheet metal & quality body work go for, one can consider such upgrades CHEAP insurance! http://pontiacstreetperformance.com/psp/rebuild455fhand02.html Got Posi? :3gears: Roger
