GM stock 12 bolt

[Ponyrider]

Do GM produce or make a 12 bolt rearend for there stock vehicles?

If so will it fit my 95 Z28?

I was told that some of SUV come with 12 bolt RE's

[fastTa]

The 12 bolt was put in production GM cars and trucks from 1964-1982.

If you plan on fabricating and/or welding on your own brackets, mounts, and perches, you have your work cut out for you. You will have to do this if you plan on buying a "factory" 12 bolt. You might save a few hundred dollars, but it really is worth just buying one that already has all the appropriate hardware already on the rear end. The torque arm mount can be especially tricky to fabricate on your own.

[Ponyrider]

Thank you! So if I have the time and the skills or know someone it can be done. Because I can get the rearend for 100.00 so would it be worth it?

[fastTa]

Thank you! So if I have the time and the skills or know someone it can be done. Because I can get the rearend for 100.00 so would it be worth it?

If it is the entire rear end for $100, sure that is a good deal. You just need to measure the width of the rear end you are going to buy from flange to flange. The stock 10 bolt is 64.75".

[Injuneer]

In addition to the width....

-Weld axle tubes to center section, verify straightness
-Remove all metal brackets
-Install your stock brackets for PHR, LCA's, shocks, springs
-Invent a TA bracket - this is not easy
-Is the carrier a limited slip unit
-Is the carrier strong enough for planned application
-Does the carrier need to be rebuilt
-Are the gears good, and the ratio you want
-Do you need C-clip eliminators
-Swap brake mounting plates.
-Swap center-mount ABS sensor, or axle mount TCS sensors
-Does it have a 1350 pinion yoke?
-If you have to narrow it, you need new axles.

I'd suggest you PM "N20LT4Bird".... he did the conversion recently.

[Ponyrider]

Thank you I PM N20LT 4Bird

[N20LT4Bird]

Yea, Fred's list is pretty much on the mark. I did the conversion last spring. It was the first time I had fabricated a rear-end. It was difficult, but if youve got a good head on your shoulders, have all the tools, and are good with fabrication, it can be done.

If you decide to do it, I would highly advise buying a used, stock 10 bolt f-body housing. This way, you can leave your current rear-end in the car and do all the measuring (theres a lot of it) and cutting on the junk housing. I got my housing from an f-body salvage yard for 100 bucks shipped to my door.

Measure, measure, and then meaure again. I did an orhtographic drawing of the stock rear, so i would have all the mearurements even after I started cutting the brackets off of it. If you are a CAD guy, that will help.

I had to shorten the axle tubes, so custom axles were required. I also added c-clip eliminator ends, that accept a press-fit axle bearing. Those were obviously welded on the tubes. The brackets were all measured precisely and welded on the 12 bolt, but you have to compensate for the fact that the axle tubes are larger on the 12 bolt. Axle tubes were welded to the housing. The torque arm bracket was the biggest PITA. You cant weld to the cast iron center section, so I had to design a bolt on (basicly) bracket. I didnt realize the torque that thing endured, so I went through like 3 upgraded designs as I kept snapping them. THe center section is an eaton posi and I also added a moser girdle. The yoke is a heavy-duty billet steel 1350 series yoke and I have a conversion u-joint (until I break my driveshaft and then I will upgrade the whole shaft with a true 1350 joint).

All in all, I had about $1400 into the build-up. So I saved about 600-700 bucks, but it was A LOT of work....and I do not have ABS anymore ....but thats not a big deal to me.

[Ponyrider]

So do you still have your final design? If so could you send them to me. I would like really look at what I going toget myself into. It maybe better to purchase if it really a problem. Thank You

[N20LT4Bird]

So do you still have your final design? If so could you send them to me. I would like really look at what I going toget myself into. It maybe better to purchase if it really a problem. Thank You

I documented it pretty well on the board when I did it.........Heres the threads with pics......this is pretty much the start....

http://www.f-body.com/forum/showthre...highlight=bolt

Heres the middle.......with a couple close up pics of the T.A. bracket. Keep in mind, this design was strengthened a lot since these pics were taken. The T.A. bracket now has a monster U-Bolt around the pinion "snout" of the housing and the bracketry was beefed up a lot, but the same basic design. Works good now!

http://www.f-body.com/forum/showthre...highlight=bolt

Heres the rear, right before I bolted it in the car....

http://www.f-body.com/forum/showthre...highlight=bolt

let me know if youve got any questions.....