12 bolt upgrade worth it?

[70chevellemalibu]

Hey all,

I have a 8.2 2:56 peg leg in my 70 Chevelle. I am not a drag racer but I do like to have some fun on the streets and will go to to local auto cross events. I currently have a 350 with th350 and eventually will be doing a 5.3 or 6.0 swap with a 4l60e, I am planning around a 400 hp car.

Id like to add a posi and change the rear gears in the future but i cant justify the going rate of 12 bolts, i found a used 12 bolt with 3:08s and posi for $1500 CDN ($1100 USD)and it looks pretty good but its still used and they are not easy to find in Canada.

Any thoughts? What would you guys do?

thanks

[Peter Mc Mahon]

I think $1500 sounds like a lot. For reference, I bought a 8.8” from a wrecker for $100, 3:55 no posi. I brought it to a ring and pinion shop in Chatham and he rebuilt it, added FRPP posi, straightened both axle tubes I had warped from welding on brackets, supplied another 31 spline axle since one of mine was worn and supplied a nice rear cover to top it off. That was 2 years ago with me beating on it. No leaks anywhere. The price was under $1100

[andrewb70]

I think $1500 sounds like a lot. For reference, I bought a 8.8” from a wrecker for $100, 3:55 no posi. I brought it to a ring and pinion shop in Chatham and he rebuilt it, added FRPP posi, straightened both axle tubes I had warped from welding on brackets, supplied another 31 spline axle since one of mine was worn and supplied a nice rear cover to top it off. That was 2 years ago with me beating on it. No leaks anywhere. The price was under $1100

Apples and oranges...You can't exactly put a 8.8" Ford rear end in a 70 Chevelle.

Honestly, I would put a different gear and post in the 8.2" and drive it. If you're not going to drag race it, I bet it will last forever with 400hp.

Andrew

[Peter Mc Mahon]

You’re right Andrew, not sure why I thought it would!

[andrewb70]

You’re right Andrew, not sure why I thought it would!

If it was a leaf sprung swap, then the 8.8" is definitely the way to go!

Andrew

[Dark Pursuit]

If you can find an 8.5" 10 bolt they are much stronger ( my axle builder thinks maybe even than 12 bolt, as 12 bolt used much smaller bolts)
And you can very affordably build that 8.2 to handle 800hp

[Zspoiler]

Maybe an 8.5 10 bolt from an 1975-77 Chevelle abd its cousins might fit.

[andrewb70]

Maybe an 8.5 10 bolt from an 1975-77 Chevelle abd its cousins might fit.

I believe the mounting points are different...very similar, but not interchangeable.

Andrew

[70chevellemalibu]

so everyone is of the opinion to rebuild my 8.2 with a posi and a set of gears? or should I just keep looking for a good 12 bolt core?

[USAZR1]

My 70 Elco has a Dart 385" sbc, TH350 w/TCI converter, and 8.2 10 bolt w/3.42 gears. The previous owner installed a mini-spool, instead of a limited slip. In the near future, I plan to install a Yukon or Eaton posi.
I'm probably pushing the limits of the 8.2 but I think it will be ok.

[andrewb70]

so everyone is of the opinion to rebuild my 8.2 with a posi and a set of gears? or should I just keep looking for a good 12 bolt core?

Add posi, gears, and axles, and rock on.

Andrew

[Interceptor5588]

8.2 will be fine unless you put slicks on it

[Zspoiler]

I would look for a 12 bolt .And or get an aftermarket one.

[raustinss]

As a fellow canuck I do know the 12 bolts are harder to find here .... keep you eyes open during the off season . About 8 yrs ago I couldn't give mine away , 3 trips to Barrie swap meet before I finally dumped it for 250 $$$$ ! . I have seen some on kijiji for around 1000

[Dark Pursuit]

early 70's nova ss 8.5" is bolt in

[andrewb70]

early 70's nova ss 8.5" is bolt in

Really? For a 70 Chevelle?!?!?

Andrew

[68Formula]

i found a used 12 bolt with 3:08s and posi for $1500 CDN ($1100 USD)and it looks pretty good but its still used and they are not easy to find in Canada.

This seems like a pretty good deal. I'd be all over this.

[raustinss]

Yeah you and everyone else lmao ... I didnt offer it up on here because A you Americans have way more "inventory " then we do and B I really had zero desire to attempt at shipping it

[Peter Mc Mahon]

OP, where are you located?

[70chevellemalibu]

I'm in Manitoba.

I priced out a posi, gears, rebuild kit and axles for my 8.2 and it put me around $1700 CDN to rebuild.

If i buy the 12 bolt i might need a rebuild and upgrade the gears to a 3:55 > one day so that puts me at $1500 + $500 for a better diff?

thoughts?

[raustinss]

If you're in Manitoba hit up HPICUSTOMS.COM.. they might have one or know where one can be found

[70chevellemalibu]

yes i called local speed shops and i have been looking on our local used online market.

[Joe_Rocket]

Did you manage to find anything yet? Several years ago, I read some budget build articles in Super Chevy or Hot Rodding on building up the 8.5. I found an 8.5 inch 10 bolt in an early 70's Nova at a junk yard. According to articles I read, the 8.5 has much of the same guts as the 12 bolts with the exception of a slightly smaller ring gear. I stripped it down to the bare housing and bought that for $50. I put about $1500 into it to have it built up with a nice posi and forged axles.

[badazz81z28]

I personally wouldn’t rebuild a 8.2 simply because I concern my self with value at the end. I would want the rearend to have value and potentially be a good selling point for the car if you ever needed to sell it.

A 8.5 can be built to be stout, but stock for stock the 12 bolt is stronger. It has a larger ring gear, the axles are 30 splines etc.

Have you considered a 9”?

https://www.ebay.com/itm/9-Ford-Rear-A-Body-Rear-End-Housing-1968-1972-Chevelle/223213876081?fits=Year%3A1970%7CModel%3AChevelle&hash=item33f8957371:g:aiEAAOxyqUpQ88In