[66_Cat_Jon]

Is this 8.2 BOP the same housing and axle setup used in the big cars? Everybody's comments seem to be about Firebirds and GTO/Lemans. I have a 66 Catalina and I remember many years ago looking to get a better ratio gear for it and places like Summit and Jegs listed BOP components but something I can't remember now was different than what I had. I haven't looked lately but back then (late 90s?) the only diff parts for a 66 full-size had to be used OEM. Anyone know anything more about that?

['ol Pinion head]

Originally Posted by Jay S

Would that 8.2 with 3.55s in a 69 Judge be an nodular (N) rear axle?

A '69 Judge optioned so it came with 3.55 gearing & Safe-T-Track, would a Nodular 8.2 PONTIAC center housing & the late 60's 4 pinion PONTIAC 8.2 carrier.

['ol Pinion head]

Originally Posted by 66_Cat_Jon

Is this 8.2 BOP the same housing and axle setup used in the big cars? Everybody's comments seem to be about Firebirds and GTO/Lemans. I have a 66 Catalina and I remember many years ago looking to get a better ratio gear for it and places like Summit and Jegs listed BOP components but something I can't remember now was different than what I had. I haven't looked lately but back then (late 90s?) the only diff parts for a 66 full-size had to be used OEM. Anyone know anything more about that?

No, the early Pontiac 8.2 rears were not used in the '65-70 Pontiac B series. All US produced '65-70 Pontiac B series rears were 8 7/8" '65-70 P Series rears. Big Olds also used a version of the P series rear. believe that was '66 model. Im NOT an Olds guy, & its been near 25 years since I crawled under a manual trans '66 big Olds to drain the r/e lube & ck out that r/e's ring & pinion.

[mchell]

never broke an axle on an 8.2 but started stripping the ring gear teeth right at 1.59 60's....always ran a diff cover with the bearing cap preloads, seemed to help quite a bit.... nothing saved the ring gear after 1.59 or less 60's

[Verdoro 68]

What are the torque/hp limits of an 8.2? I have to imagine they were close to the limit with the stock 400 application since they stepped up to a 12 bolt with the 455s in '70.

Wondering what the likelihood is of my rear end (3.55 4-pinion Nodular) surviving a launch on street tires vs. drag radials with 450ft/lbs of torque at the rear wheels? Trying to decide if I should just bite the bullet and replace it before I go beating on it.

[punkin]

Have not broken an axle but came very close to it. After many years of street tire drag racing, no issues but then decided to put slicks on. 455 with TH350, 3.55:1 rear gears. First pass went really well, the second pass not so well, noted a 1 wheel burnout. When I got home took the cover off and pulled the axles...one axle was twisted at the splines. Differential was done. This was an old cone style unit. Machine shop said it couldn't be rebuilt.

Currently running 9" with wavetrac and currie 35 spline/3.50:1 setup.

[b-man]

Originally Posted by Verdoro 68

What are the torque/hp limits of an 8.2? I have to imagine they were close to the limit with the stock 400 application since they stepped up to a 12 bolt with the 455s in '70.

Wondering what the likelihood is of my rear end (3.55 4-pinion Nodular) surviving a launch on street tires vs. drag radials with 450ft/lbs of torque at the rear wheels? Trying to decide if I should just bite the bullet and replace it before I go beating on it.

Replace it before you give it another thought. If it’s the original rear then stash it under your workbench and if not sell it to recoup some of the cost of a good aftermarket 12-bolt.

Why chance ruining your good and valuable N case 8.2 just to end up buying what you knew you needed anyway ?

[Jay S]

It would probably be helpful to mention which version of the 8.2 got broke, a grey iron 8.2, or a N case 8.2. N case should be fairly strong versus the grey.

[SD455DJ]

The Tempest in Post #15 is Paul Glasgo’s super quick Magnum 400 tribute. Paul’s Tempest Hardtop (called T-37 when introduced in Spring 1970) was a 350 2-bbl/ TH350 car originally, so had the gray iron center section with 2.56 gears. There are a couple of magazine write-ups about the car online to read more about the build. At the 2017 Pure Stock Drags Paul pretty much destroyed the gray iron center section during the burnout, but this is after 10 years of drag racing the car at our race, F.A.S.T. races, and other events (Hemmings Muscle-palooza’s, Tripower Nationals, etc.). From our information (the tech card every racer fills out at the race), Paul listed the trans as 4-speed and the rear end as 3.90, so a recent change from the TH400/4.10 he was originally running in the car. That 8.2” 10-Bolt took more of its fair share of abuse and the new 4-speed probably was the final straw the broke the 10-bolt’s back.

My carnage story...my ’70 Lemans 4-dr sedan came from the factory with an M20 4-speed trans and a 3.23 Safe-T-Track 8.2” 10-bolt rear end (with the grey iron center section). It survived well behind the original 350 2-bbl engine. In 2015 we swapped in a rebuilt ’70 YH code 360 hp 455 (small valve) from a Bonneville that dyno’d at 390 hp and 512 lbft of torque which that caused major havoc to that rear end. All it took was one eased-in full throttle blast from a roll in 1st gear that brought on the most extreme wheel-hop I had ever experienced for just a split second. I got out of the gas immediately and there was a clunk and a side-to-side shimmy as I came to a complete stop. After letting it sit a minute, I then just eased it back home. Fortunately, it didn’t make any more noises or lock up on me. The 10-bolt came out soon thereafter and we sent a 3.07 12-bolt from a ’70 GP out to be rebuilt along with a new driveshaft made. We haven’t opened up the original 10-bolt rear end yet, but we know there was some damage done, maybe a tooth or two off the ring gear…?

Dennis

[Jay S]

Maybe someone can answer some more questions I have, that could be helpful on strength variations for the 8.2’s for street duty, and which upgrades are worth it for more street and strip. We went yesterday too a large salvage yard that specializes in 60s and early 70s GM cars. Must have been a couple hundred Chevelle’s. In doing so we were going through piles of rear ends, looking for N case 8.2s, and 8.5 from a 71 or 72 Olds or Buick, or a 12 bolt that could fit a friends 66 Tempest. From going on the scavenging hunt and 3 of us looking thru piles and piles rear ends, comparing notes, maybe someone can clear up some things we concluded we don’t know.


1.Does the N case 8.2 have a stronger alloy axles? One of the guys that was with me thought he remember they did.

2. When was the N case introduced??. We could not find info on anything before 68 for a N axle. We found a 68 N with 3.55s at the yard. One internet source said the N case came out in 66 though?

3. One of they guys that I went with said he talked to someone that said all 4 pins posi’s are N cases. But we have an untouched 67 4 pin with 3.36 that is not a N case. So that must not be true. But maybe there were not N case available at all in 67, and the 68 3.36 was an N case? Or did the 3.36s ratios never come with a N case. We all concluded we don’t know.

Appears to me the N case is the difference between shearing teeth off the ring gear, or ripping the pinion out of a grey iron case.

['ol Pinion head]

On the he forged axles, you will have to look at the outer surface down the axle. Are they rough looking, or look machined? '67 models were first to receive the N cast center housing.

['ol Pinion head]

just on low ratio STT coded rears. Your 3.36 is an abnormally, typ the N's started with 3.55 ratio choice. '72 is another abnomilly, ive had two 3.23 STT coded 72 Pontiac Abody 8.2 STT rears that were built on a remaining tapered axle bearing end N housing.

['ol Pinion head]

On early factory early 4 pinion Pontiac STT carrier installs, I've pulled several out of late '66 production Pontiac 8.2 rears. They appeared to be factory installs,but could have been in service, replacing factory 2 pinion carriers.

Not true on #3. I've owned half a dozen mid ratio 4 pinion STT carriers & factory 3.23's out of '69 SJ GP's. There was even a factory 4 pinion Single Track Pontiac 8.2 carrier that was used in these!

[AG]

I have a 1971 8.2 out of a GP with a 3.07 4 pinion STT.

[Jay S]

Originally Posted by AG

I broke one on the drag strip launching a 4 speed. Broke the front of the housing and the driveshaft came out with the pinion still attached. Everyone loved that I dumped 2quarts of gear oil on the track.

What was that in?

[AG]

I had it in a 1965 LeMans. I got severe wheel-hop off the line and didn't get out of it soon enough. The carrier and axles stayed in but the whole front of the housing/pinion support blew apart.

[242177P]

Originally Posted by Jay S

But maybe there were not N case available at all in 67, and the 68 3.36 was an N case?

Impression that I got (limited to 67 A-bodies) is that if/when the N case was introduced it was reserved for deeper gears like the 3.90? Dunno.

[Sirrotica]

1970 Judge 4 speed RA III, with a 3.55 axle, posi, street tires. Powershift 1-2 shift sheared 2 teeth off the ring gear, about a 1/2 tooth of the pinion, and broke a piece out of the front of the center section, about 1 inch X 3 inches.

1965 GTO convertible, 389 .060 over, 12 to 1 pistons, big cam 4 speed, 3.90 axle 1-2 shift on fairly skinny street tires. Blew the 4 pinion posi into 2 halves, and ruined the ring, and pinion.

The guys I hung out with mostly owned GTOs, we were changing rear axles in them constantly during the 70s. Not one of the cars had slicks, nor were these axles being blown up on a drag strip, all on the street. The rear axles were just marginal for their intended use, with a good running Pontiac in an A, X, or F body.

There are many things shared with the 55-64 chevy Hotchkiss removable third members, and the 8.2 Salisbury GM rear axles. When I was about 12 YO one of my neighbors had a 425 HP, 409 1963 Impala, the third member was out of it, as much as it was in it. Anyone that was around in that time period knew that the chevy Hotchkiss rear axle was the achilles heel for chevrolet. GM then transfers the similar designed parts over to the A, and later the F, and X body cars knowing without a doubt that the strength and design wasn't up to snuff for performance cars, with high performance engines. All one had to do is go to a junkyard during that era, and see the core pile with all the destroyed 8.2 axles stacked up like cordwood. I worked 40 hours a week as a mechanic, and had two wrecking yards as the sponsors for my dirt cars, I spent many hours in wrecking yards during that time period.

Pontiac, and olds had the 9.3 Hotckiss style from 55-64, those axles were strong enough to run in rail dragsters, and funny cars of the era. Guys that ran full size chevys at the dragstrip would transplant Pontiac/olds axles under their chevys if they were serious drag racers.There just isn't enough mass in those 8.2 axles for sustained abuse.

FWIW, switching from 4 speed cars, to T 400 equipped cars help extend the life of 8.2 axles on the street.