[92GTA]

The 1969 that I bought has a peg leg with either 2.73 or 3.08.

I want to upgrade it to a 3.73 and also get a posi, limitied slip, zexel-torsen, or whatever I need.

I don't know anything about these 1960s rear axles. In my 1992 it was easy to swap what was in the factory 10 bolt (2.72 limited slip) for a 3.42 zexel-torsen out of a 2002 Camaro SS.

What do I need to do for the 1969 to get it upgraded similarly?

Thanks!

Alex

[rexs73gto]

You can buy the posi unit NEW & same with the gears direct from several places like Summit, or Jegs & then just install them as you would for your 92 car. The cost for all the parts you need new can be gotten for about $ 600.00 & it will al be NEW.

[tom s]

With your 461 a 3.73 might be too low.I would look more up around a 3.42 ish.Tom

[Squidward]

Finding BOP 10 bolt stuff is starting to get tougher as the aftermarket sees a dwindling market. You need to figure out exactly what gears you have, because that will affect your options based on carrier breaks.

There are a few options.

If you wanted to keep your current gears, you could get a Powertrax. They work, are a drop in replacement for spider gears, but they are clunky. It may drive some people batty. You could do that without doing a ring/pinion change and setup. That would be a low cost option.

Or, you could source a new posi, like an Eaton or Yukon which requires 3.36 (3.31 for the Yukon) and up gears. So 550-ish for posi, 250-ish for gears, another 100 for bearing/setup kit. So we are now at around 900 for parts. If you DIY, then you need to have some specialized tools. That might run you another 200.

You could keep the same ring/pinion gears (if between 2.93 and 3.23), and get an Auburn hi-perf series posi, but those aren't well regarded for real heavy use. I've never used one. They run a little over 400, plus another 100 for setup/bearing kit, and tool cost. Auburn makes a Pro series, but that is for 3.31+ gear sets (not you). The Pro series costs as much as the Eaton, and you'd still need a gear change.

And still at question is the strength of the 8.2 BOP. I read many threads where people fragged them at reasonable HP levels, and a few stories where they survived many launches. From my research, they are not as good as the 8.5 10 bolt. I found a 73 Nova 10 bolt for my 67 FB, built it with 3.73's, new posi, and Moser axles. I came in close to 1k doing it myself. The rear end was a bolt in, but needed 3/4" shorter driveshaft. It was also 1" narrower overall than my 8.2 bop.

8.5 stuff will be noticeably cheaper.

If you want to do 8.5 stuff, then a Nova rear fits 1st gens. But Nova's used 8.2 Chevy's up through 71 or 72, and those are worse than the 8.2 BOP. A second gen Firebird 8.5 will fit, but you will need to have the spring perches relocated/replaced, and shorten the driveshaft. The rear width for the 2nd gen is the same as the first gen Firebird with the 8.2 bop. You could still probably find a 2nd gen rear out there from a mid to late 70's T/A with 3.08's and a posi.

So... your head spinning yet?

[Squidward]

Originally Posted by tom s

With your 461 a 3.73 might be too low.I would look more up around a 3.42 ish.Tom

Yes, agreed. I have 3.73's behind my 350, and it is now traction limited on standard street tires. Behind a 461 it'd be a smokefest.

[92GTA]

Yeah, after sleeping on it last night I came to the conclusion of 3.42 right before I fell asleep haha!

I won't be installing myself, never done gears so I don't know how to set lash or anything. I'm just going to have my old transmission guy throw it in for me. My budget right now for sure won't let me swap to a better stronger axle

So these old rear ends are called a 8.2" BOP? What does BOP stand for? I see these old ones are also 10 bolts.

EDIT: Wow this old stuff is WAY more expensive than the new stuff then. I got a brand new, take out, zexel-torsen with 3.42 gears for $200 on eBay from SLP for my 92.

But for my 69, I'm looking at triple or more for something comparable?!

The least expensive limited slip on Summit that will work with 3.42 gears is an Auburn $450, CRAZY!

https://www.summitracing.com/int/par...model/firebird

Summit does not even have 3.42 as an option for "GM 8.2 in., BOP axle" ring and pinion gears? Only 3.36 and 3.55, is that right? What color/tooth speedo gear do I need for my TH350 with 3.55? - GOT IT, yellow! http://www.ebay.com/itm/NOS-GM-1967-...-/381653235799

EDIT: Just found the same Auburn posi on eBay for $388, much better price:

http://www.ebay.com/itm/AUBURN-GEAR-...-/262337045978

EDIT: Found some 3.55 gears for $149:

http://www.ebay.com/itm/GM-1955-64-C...dXq5rA&vxp=mtr

Should I go 3.55 or 3.36? I want great acceleration at the track with my DOT slicks so I'm thinking the 3.55.

Wow, so about $575 total plus install labor, parts, and gear oil. Ok so $700 lol. FML

[b-man]

Don't waste your time and money on the weak BOP ten-bolt, upgrade to a twelve-bolt or an 8.5 corporate ten-bolt.

[92GTA]

Yeah I'm starting to agree, but then I'm talking even more money that I've ran out of lol. Time to side line the original rear in the garage with the original engine and soon the original trans if I can ever afford a built TH400 someday.

Maybe I'll just wait and save because yeah, $700 at a weak rear sucks. If I get another rear, I can get one with disc brakes too and perhaps even a posi with the gears I already wanted with it.

Hard to believe the BOP 10 bolt is weaker than the newer 10 bolt, which is weak too! Never have looked into a 12 bolt, what sort of GM years and vehicles are those in that will fit Firebirds and would have disc brakes? Then I can start keeping an eye out and saving.

[OCMDGTO]

BOP=Buick Olds Pontiac(not sure if you were joking or not)
Been down that road after breaking my 10 bolt. Just didn't make sense putting a grand into it so I could break it again. That 461 is going to put a beating on it. Mine survived hundreds of burnouts on street tires before it broke.

[92GTA]

Nope, I've never heard of BOP lol, I'm new to old Pontiacs. Thanks!

[silverbullet07]

To muddy the water, 67-69 Firebird 400's with the safe-T-Track 3.36 and higher "numrical" had HD Nodular cases. They were a lot more thicker in the pinion areas were the Grey iron housings were weaker and broke. The nodual cases had a N near the Pinion Yoke on top to idendify as well as different part numbers. http://www.firebird400ho.com/nodular...nd-date-codes/

Also when you are looking for a ring and pinion, when they say GM make sure it is for a BOP 8.2 and not chevy 8.5 they are different.

[92GTA]

Gotcha, I'll keep and eye out for those. Mine is an original 350 car so it won't have it :/

[ponyakr]

"...Never have looked into a 12 bolt, what sort of GM years and vehicles are those in that will fit Firebirds and would have disc brakes?

The 12-bolts were used in some Chevelles, Camaros, and Novas, from the mid '60's thru at least '71, I believe. Some '70 Firebirds, and early '70's Pontiac A-bodies also had 'em. The only ones that would be a bolt-in would be those from the 1st gen Camaros & '68-up Novas. The A-body rears would need leaf spring perches added. And the other leaf spring models would need the perches moved to the correct location for the 1st gen springs. Disk brakes would have to be added. Kits are available.

BUT, since these have not been made in a long time, and have been in such high demand for so long, they are not cheap at all. Most that I've seen lately are priced well over $1000.

http://www.ebay.com/itm/1968-69-CHEV...lXhUCF&vxp=mtr

http://www.ebay.com/itm/CHEVELLE-12-...3D172250038353

http://www.ebay.com/itm/1970-Firebir...pUY-LN&vxp=mtr

http://www.ebay.com/itm/1970-Z28-Cam...JXetty&vxp=mtr

You can buy a new 12-bolt, with disk brakes, for somewhere around $3000-$3500.

http://www.moserengineering.com/comp...musclepak.html

http://www.ebay.com/itm/1968-72-CHEV...FXdIKp&vxp=mtr

http://www.ebay.com/itm/CUSTOM-BUILT...hRsA5u&vxp=mtr

A cheaper way is probably to find a cheap 2nd gen 8.5, then modify and upgrade as needed. An X-body(Nova, Ventura, Omega, Apollo) 8.5 might be even better. At least the spring perches would be in the correct place. Then you can buy an Ebay posi/gears/bearings kit and you'll know what you have. Stronger axles are also a good idea.

http://www.ebay.com/itm/GM-8-5-10-Bo...3D231995761778

http://www.ebay.com/itm/CHEVY-GM-8-5...1XdBHF&vxp=mtr

[Squidward]

Originally Posted by b-man

Don't waste your time and money on the weak BOP ten-bolt, upgrade to a twelve-bolt or an 8.5 corporate ten-bolt.

+1.

The couple hundred bucks you would save by NOT buying the more expensive BOP stuff and buying 8.5 10 bolt stuff might fund a nova 8.5 rear end. Or a 2nd gen 8.5 for perch relocation.

12 bolts are tough to find (expensive). For me it was either find the Nova 8.5, or get a 12 bolt housing from the aftermarket as a bolt in. I found the Nova rear for $150 locally.

So... starting in order of least desirable in terms of strength of 10 bolts: 8.2 chevy, 8.2 bop, 8.5 chevy/corporate. Factory 12 bolts are stronger than factory 8.5's due to axle size, but 8.5's can be upgraded to be their equal. Ford 9's are the strongest. I have no idea where the Dana/Mopar stuff falls in this list.

[68400BIRD]

Give Brydon at Quick Performance a call 641-751-8060. They are out of Iowa. You can get a Yukon Posi and gears for a 8.2 for around 650.00. If you can find a 8.5 out of a nova it will even be cheaper.

[92GTA]

I just ordered this setup for the same last night

http://www.ronsmachiningservice.net/...posi-gear-pkg/

Thanks tho!

['ol Pinion head]

So much ignorance in this thread...
For the 47th time, the only folks that refer to a Pontiac 8.2 10 bolt as a 8.2 "BOP" are the parrots of a bunch of early aftermarket parts suppliers like Zoom. The differential is an 8.2 PONTIAC. The gray iron housing and std duty axles, carriers, gears were cast and machined by Pontiac Central foundry. Pontiac drivetrain engineers were not idiots, they were trying to minimize warranty issues. there is a reason Nodular iron center housings were specc'ed for '67-69 Birds with lower gear ratio Safe-T-Track differentials.

['ol Pinion head]

Originally Posted by 68400BIRD

Give Brydon at Quick Performance a call 641-751-8060. They are out of Iowa. You can get a Yukon Posi and gears for a 8.2 for around 650.00. If you can find a 8.5 out of a nova it will even be cheaper.

can Brydon box you up and ship you the pinion support needed in a gray iron 8.2 housing to support 500 ft lbs of torque?

Throwing good money at a kit consiting of a cheap chinese gear set and posi arent going to upgrade uthe strength of the 8.2 gray iron rear, the main weakness of ALL of all of the 8.2's is the lack of pinion support.

['ol Pinion head]

Originally Posted by Squidward

+1.

The couple hundred bucks you would save by NOT buying the more expensive BOP stuff and buying 8.5 10 bolt stuff might fund a nova 8.5 rear end. Or a 2nd gen 8.5 for perch relocation.

12 bolts are tough to find (expensive). For me it was either find the Nova 8.5, or get a 12 bolt housing from the aftermarket as a bolt in. I found the Nova rear for $150 locally.

So... starting in order of least desirable in terms of strength of 10 bolts: 8.2 chevy, 8.2 bop, 8.5 chevy/corporate. Factory 12 bolts are stronger than factory 8.5's due to axle size, but 8.5's can be upgraded to be their equal. Ford 9's are the strongest. I have no idea where the Dana/Mopar stuff falls in this list.

Let's disect this ..

Totally agree, 12 bolt 1st Gen F body rears are expensive. Have several in the racks and have built over 4 dozen early Camaro/Nova rears. Nice clean factory posi coded '67-69 housings, they are ending up in NICE early Camaro restorations. Want to save, ask your builder if he has a '65-67 "Chevelle" 12 bolt that has had the perches whacked off. those can only be built up as leaf spring rears & the housing doesn't have expensive restoration value. 9"s...until one upgrades a stock Ford 9" with Nodular case, Daytona pinion support, sorry, the strength is debatable. Have examined too many damaged budget built 9"'s. For years pulling cores I grabbed every narrow (Granada) 9" as well as TracLoks out of pickups. Never had a hard time selling them, but for what they went in, power wise, an 8.5 or upgraded 12 bolt posi rear would have sufficed.

The 8.5 "Nova" housing makes a good budget build. typically the stock axles in these are pitted at the wheel bearing contact surface & for strong performance use, some thought needs to be taken as to axle retention & axle strength. Have built well over a hundred 8.5 X body rears off the monoleaf & multileaf "Nova" 8.5 housings. The 8.5 X-body rears are same width as a '67-69 Camaro rear, 1/2 narrower on each side than the original early Firebird rear. The 8.5 housing has more pinion support than even the stock 12 bolt hsg, so less pinion deflection. Upgrade the 8.5 to a 30 spline Eaton Posi, or 33 spline spool, quality set of gears, a pair of Moser axles, depending on how hard you're launching, a fitted lh billet steel cap... a very strong rear.

Desiring exact same width as the early Bird with superior design tapered bearing bolt in axles, here's a route have gone several times. Many times when hitting boneyards, I've pulled early 8.5 A body housings out of housing core piles...i always ck em out real close. Several times now have encountered an upper control arm perch on a 8.5 Abody center housing which the loop is cracked as the perch took a good whack from another rear being dropped onto it. Have ran across this on 12 bolts and even a '68 Nodular 3.90 coded GTO rear Dumb stuff often happens in busy yards when it comes to core out time & the mobile crusher is on its way. These lightly damaged housings were not able to be built up as desirable performance 8.5 A body rears, but, each time was able to buy the core cheap. Back in the garage, careful trimming & grinding removed the cast upper perchs, as well as the lwr control arm & coil spring mounts. On the bench, in the jig, then I came back in and tacked on welded multileaf early F body leaf spring perches which have reinforced. Off the bench with the housing and the lineup bar to an old friend, who has always treated me well when it came to firing up his TIG welder. End up with a fairly clean hsg, tapered bearing hsg ends, ready to build. The stock bolt in tapered bearing '71-72 A body axles are stronger than the flared design 8.5 c clip axles & will usually hold up in a fairly strong street build. Throwing 500+ ft lbs of torque at sticky rear tires in heavier car, its time to upgrade to Moser axles. Might as well plan for it from the beginning and go 30 spline with an Eaton. Not there yet, power wise, saving for say the bill on the engine build, can always order the 30 spline Moser axles and use a cheap used GM Auburn 30 spline posi unit from a Caprice. Then when that new engine is ready and the bank acct balance is there, buy a new HD Eaton 30 spline carrier and have it installed.