I am looking into swapping out my 10 bolt for a 12 bolt. Are there any direct swap 12 bolt rearends? What type of car are they found in?

 

None will fit a 3rdgen car. If they did, everyone on this site would be braging about their 12-bolts. Do you see any Posts about them. That is your answer.

 

What makes them not fit? Length of rearend? Size of carrier housing?

 

Biggest problem I think is the lack of a torque arm mount.

 

Moser or Strange. Either way, around $2000.

 

I agree. If you wanted to convert one it would be easy enough to weld your springs, lcas, and etc on, but you'd have to make your own tq arm mount or your own torque arm to mount off your mounting tabs. The 10 bolt and 9 bolts are cast into the housing itself.

$2000+ without most options for aftermarket ones. Aftermarket ones normally provide you the new bracket (at least on the 9"s) to accept the torque arm or provide mounting ears on the housings and a different tq arm. You still have to make sure the bracket or bolt attachments are correct and sturdy. I've read about companies using shorter bolts and they eventually came loose got slop in the bracket on the tq arm and broke it. The tq arm provides the correct pinion angle without it the rear will pivot and tear up stuff (driveshafts, floor pans, etc).

 

The lack of a torque arm mount is the biggest issue but if can overcome that by fabricating something to work or change the rear suspension to something like ladder bars, your next issue will be width. The car 12 bolts are different than the truck 12 bolts. The car 12 bolt is actually stronger. Most 12 bolts you'll find in the junkyard are from trucks and will be too wide. The closest 12 bolt that will be the proper width would be from a first gen f-body or Nova etc. Chances are if you could find one, you could sell it for enough to buy an aftermarket bolt in diff. I'm not sure if any of the second gens had a 12 bolt option but they would be just as valuable.

 

Now to long ago my '86 got a 12 bolt fabbed in. here are the pics

 

Installing the spring, shock, LCA mounts etc is the easy part. Do lots of measurements then cut them off a donor 10 bolt and weld them onto the replacement diff. Any picks of what you did about the torque arm? Looks like a G-body diff with the factory triangulated 4-link mounts on top.

 

This is a nice set up you fabbed, any other pics? I was going to do this in my 85 years ago which I have since sold, an early Impala is the correct width more or less backing plate to backing plate so that is a good candidate

What rear did you use?

We will soon do a swap like this into my friends blown 383 6 speed TA that we are about to put together..

Regards, Tim

 

this is all worthless without pics/info of what you did to install the torque arm....

 

The second gen 8.5" 10 bolt is still a good strength upgrade, and is something like .5" off of exact width. Problem of torque arm still exists, but at least this rear is close. Bolt pattern for wheels is the same too.

 

I'm not sure if it was '70 only, but an early 2nd gen 12-bolt did exist and is the same width as a 68-72 A-body (which are semi-easy to swap into a leaf 2nd gen.)

The narrower 1st gen rears are the same width as the 64-67 A-body.
Not with those big axle tubes and wide-spread UCA bushing mounts it doesn't.
The '87 Buick GNX (not the Grand National) had two attachment points on it's cast rear cover for the torque arm. It would be straightforward to duplicate that for the 82-02 F chassis. Fun thread re: this topic matter here: https://www.thirdgen.org/forums/tran...5-swap-go.html

 

What 12 bolt did you use? I am guessing a 68 - 72 Chevelle? which is the same width as a mid 70s Camaro 8.5 corporate 10 bolt...I am thinking this may be the way to go, what is the overall width when measured inside the backing plate to the other backing plate?

thanks, Tim

 

I just sent this pic to my friend, so that he can measure up the rear axle tonight...would be great to know what your 12 bolt meaures, this is what I meant about the inside width - any help would be greatly appreciated. i am not worried about fabbing the torque arm mount etc, as I do a lot of welding and fabrication, lucky to have a mig, tig, arc welder, chop saw, plasma cutter etc

 

The 1970 Trans am came with a 12 bolt and 70-72 camaros had a 12 bolt in the Z28 and big block cars if memory serves. The second gen 10 bolt is a great rear and the 79-81 trans ams came with posi rear disc. All 80-81 turbo trans ams came with posi rear disc brake rears. I think it was code J65 and the WS6 cars came with posi disc brakes. In 79 they were ordering so many they almost ran out and so they made a WS7 code which meant everything a WS6 had except rear disc. I have two 81 Z28s with posi rear disc brake rears out of trans ams and I have never had a problem out of them. I have blown up more turbo 350 transmissions than anyone alive but never lost a rear. I think the ford 9 is probably the best since you can change center sections so easy and I have one in my 89 iroc with a locker and it is great.

 

My dad saw a 12 bolt for a 68-72 Chevelle online tonight, we went to look at it.....as my dad and I wheel and deal with some parts etc....could believe my eyes....it was all set up for a 3rd generation Camaro/Firebird. Only thing that was not fabbed yet was the torque, so we will do that, then will go in my friends car.

 

so you're saying i can use a ford 9 for a strong change to the stock 89 rs rear? I need help finding out what i can do.

 

any more pics or info on the 12 bolt swap?

 

Installing a 12 Bolt in a Third Gen is too much of a hassle. Purchasing a housing out of a Camaro or Chevelle is very expensive. It is going to cost about $1100.00 for an Eaton Posi, Motive Gears, Moser Axles and Timken Bearings. Then you have to have to factor the cost of fabricating the spring pads and shock mounts. Until someone figures out a way to mount the torque arm bracket to a 12 Bolt or 8.5 10 Bolt, it is just not a cost effective option.


I just bought a housing form Quick Performance:


http://www.ebay.com/itm/251396139844?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

 

Take out of crate, bolt into car = Too much of a hassle?
I think cheap is too much of a hassle! Doing it wrong or doing it poorly is a long term hassle.
But what do I know, it's just my opinion and just my car.

 

Now that's the way to put a 12 bolt in a 3rd gen. Mark Williams makes a great 12 bolt for these cars.

 

I never said anything about doing the job cheap. I am installing a 9" Ford in my 92 Camaro. I am also using a Moser Wavetrac with a Nodular Case.
Also, I am not modifying a 67 - 69 Camaro 12 Bolt or Chevelle 12 Bolt. These housings are far too valuable to Camaro and Chevelle owners to modify for another car. Factor in the initial expense and the cost of fabrication, it is easier to start with a housing that is a direct bolt in. As long as you use quality parts, you will have a stout rear differential.


Here is a link showing the Mark Williams 12 Bolt:


http://www.hotrod.com/how-to/transmi...-buyers-guide/


It looks like a great 12 Bolt. I just don't have $3100.00. A Ford 9" gives me the opportunity to build a strong rear that fits into my budget.

 

Hi Freddie,
If I could afford a Mark Williams 12 Bolt, I would have went in that direction instead. You know me, I have no shortage of 12 Bolt stuff.


Tory

 

Tory, I didn't know you had a 3rd gen Camaro.

 

Hi Freddie,
I just bought a 1992 Camaro RS last month.
This is the car:


http://www.superchevy.com/how-to/pro...o-small-block/


http://www.superchevy.com/how-to/cha...-installation/


http://www.superchevy.com/how-to/exh...haust-upgrade/


My friend Greg Lovell who owns AntiVenom in Seffner, Florida is doing the build for a magazine. The small block is gone, so we decided on a LS swap with a 4L65 transmission.


Here is my 68 Camaro in the movie, "Not Fade Away"




At 40 seconds, look for the red guitar. I have been lucky with the movie and with Dale M regarding photos of my original 64 Malibu SS. The 64 will be featured in "Chevelle SS 1964 - 1972 A Musclecar Source Book."

 

Cool, I've tried for years to get my Camaro in a mag, and yours has already been in one more than once.

 

I love my dts 12 bolt..well worth the money and confidence.

 

Do any of these have provisions for running a stock disc brake set up with parking brake?

 

Yes, you can use the 10 bolt disc brakes if you order the rear end with the correct housing ends. The Moser housing ends are 7900FM.

 

Thanks!

That's good to know because depending on if my rear-end survives or not, will determine which direction I go. Either the rear first, or big-brake upgrade first. Either way, the key for me is that my emergency brake has to work. If I can mount the factory rear-disks, then it should be a non issue.

 

https://www.strangeengineering.net/p...-bolt-rear-end

 

https://www.moserengineering.com/rea...and-axles.dept

 

I wonder if this ez2cdave guy supports his thirdgen.org habit by being a Walker on TWD? Sure does a good job w zombie threads.

 

The original question asked at the start of this thread is still valid for others considering a 12-Bolt rear end . . . Why not update it with some current information ?

 

Necro man

How many pages of the forum do you have to wake up long-dead threads with "new" postings about this old book?

C'mon d00d, I don't know, and don't care, what the motivation is; it's humorous, no matter what.

 

Well, it gives you something to read, doesn't it . . . On to the next "resurrection" !