I found a guy who has a 12 bolt posi from a 69 442 olds for 400 bucks. Will it fit in my 70 chevelle with no modification and is it a good deal?

Yes,it will fit.
$400 isn't too bad of a price,especially if it has 3.08 or 3.23 gears.

I did a little more research and wasn't aware the olds rearend is different internally than a chevy 12 bolt. Its said it is basically a 10 bolt inside and weaker. I think im going to pass after reading that.

Kirk, good call. Your right, its a BOP rear.

I also saw a 12 bolt chevy rear for 200 on craigslist but I dont know a lot about rearends. OF the research I've done they look somewhat simple to rebuild. I looked at currie and its about 2500 for a nice bolt in 9" rear ready to go, but that is just way to much for me. I have my 350 being rebuilt and I am maybe looking at 350 horse. The reason Im thinking of switching to a 12 bolt is because I have a 8.2 rear and its basically the same cost to rebuild. So if I am going to do this why not get a 12 bolt for a bit more and do the work while my 10 bolt sits in the car. I believe my logic is sound, anyone disagree?

How much is it typically to swap the internal parts out?

You might want to go look at it...1968 and 1969 Canadian built 442's came with a Chevy 12 bolt rear.

Even if its not a Chevy 12 bolt,if it came with 3.08 or 3.23 gears and you aren't going to be putting 550/ft lbs. TQ thru it on slicks at the track its a good deal.I usually get $700-800 for for an Olds 12 bolt posi around here to someone building a numbers correct 68-69 442

Ill check it out not sure on the gears.

I have a BOP in my 72. It fits, it works, with adjustable upper control arms it would sit a little better, but it's beats the one-wheel-peel until I can come up with enough scratch for a Chevy 12 bolt.

See if the P side axle tube has a two letter code stamped on it (more likely it will be a Capital Letter and a Number).

If it's an original posi coded rear then it's got some good value and you may be able to make some $$ (which we all can use these days).

'68 and '69 442s came with both the "O" type axle or the "C" type.

If you find a code and post it I can post the ratio that the code indicates as original.

Where are you located???

what does BOP stand for?

what does BOP stand for?

what does BOP stand for?
Buick
Oldsmobile
Pontiac

For a 350 HP application, it isn't like the extra durability offered by a 12 bolt rear will be needed. So if it's the posi feature that is the main thing that you're concerned about, then for a little over $400, you can always install one of these in your present 10 bolt rear which will convert it into a posi, and merely replaces the spider gears, and doesn't even require that you touch the ring and pinion gears at all. They also have an even less expensive model too, but I believe that their cheaper model make noise around turns. These "No-Slip" ones are suppossed to be quiet.....

http://www.summitracing.com/parts/PWT-92-0782-2805/

I had a PowerTrax in my 00 GMC and it would make some noise but it did work REALLY well. My wife hated it because when she would goose it around the corners it would chirp the tires, If you took off a little slower it was fine.

LK

Thats posi looks good but I was thinking of some lower gears. maybe some 373s. I believe its in the 2s now and doesn't have much pull off the line. I really dont drive much highway so it would be nice to have some better gearing.

I had a PowerTrax in my 00 GMC and it would make some noise but it did work REALLY well. My wife hated it because when she would goose it around the corners it would chirp the tires, If you took off a little slower it was fine.

LKWas it a Powertrax "LOCK-RIGHT" or a Powertrax "NO-SLIP" ? The "Lock-right" ones are those that I mentioned that are less expensive, but I believe they aren't as quiet as the "No-slip" ones are.

Thats posi looks good but I was thinking of some lower gears. maybe some 373s. I believe its in the 2s now and doesn't have much pull off the line. I really dont drive much highway so it would be nice to have some better gearing.Oh, I see. Then it isn't only the posi action that you're looking for. In that case, then I understand why you're considering the 12 bolt rear.

Was it a Powertrax "LOCK-RIGHT" or a Powertrax "NO-SLIP" ? The "Lock-right" ones are those that I mentioned that are less expensive, but I believe they aren't as quiet as the "No-slip" ones are.

I'll have to look at the book, I believe it was the quieter one.

LK

Oh, I see. Then it isn't only the posi action that you're looking for. In that case, then I understand why you're considering the 12 bolt rear.

Yeah but its not a huge deal if I don't get one right now. I just figured 400 was within my budget. Im going to pass on the olds 12 bolt though. I think I can find a chevy one and just do the gearing or posi later if it needs either. I was quoted $1500 for a rebuilt one but I just dont have the money to spend right now. i just had my engine and heads rebuilt so I'm strapped.