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I picked up a 12 bolt carrier and after hours of research I think I have a 10 bolt housing corporate carrier????? It came with a GM ring gear. It has twelve 7/16" left hand bolts and the inner diameter of the ring gear measures appox. 5.32 vs. 5.42 on my 12 bolt 4.56 gear.

Help.....Thanks, Kurt

yES THIS IS A EITHER 28 OR 31 SPLINE UNIT.
used from 1971-1984ish era. Will have a 10 bolt cover and 12 7/16 left hand threaded bolts

There is NO aftermarket support for this rear at this time... Do you have a pinion? snap some pictures of it also.

this could be a 8.75 or 8.875 carrier.

How about the casting number 248 250 ??? something like that? This way we can get you a carrier ratio break for the unit.

This unit will be a difficult match for any thing else but the FULL size cars. I have heard some guys retro fitting it into a CAR 1965-1972 chevelle, camaro and impala housing BUT have yet to try this. As you will need shanked bolts 7 /16 to 3.8 24 thread. Also you will have to use 28 or 31 spline custom axles...So it may not be worth the effort after the cost. ?? Jim

Thanks for the reply Jim. This site was very helpful for me. I got really lucky, the guy I bought it from let me return it with full refund. It won't fit my 69 Chevelle and I was worried I that I was going to be stuck paying for $165 for a paperweight.

I believe it was a 8.75 because my ring gear was roughly 1/8" bigger on the ID.

Thanks again, Kurt

Glad we can help. I am sorry you did not get the correct part. We ALways have posi units here. If you car is a keeper. I would suggest you pay a little more and get a NEW posi unit. we have them for 389.00 NEW 3 or 4 series unit

What ratio are you running in your Chevelle?

What are you plans for the car? IE drag racing street cruzin, burn outs, light to light action etc. JIm

My car is a 1969 Chevelle SS396 300 Deluxe Post Sedan. It's a street/strip car. I currently have 2 rearends for the car. One is a 3.07 posi (street/cruising) and the other will have 4.56 (strip). I have a set of 4.56 gears for a 3 series carrier.

Are the carriers that you have Eaton?

Kurt

Well you can also try a mini spool (100.00) and a open 3 series carrier (50.00 ) as long as you are not dumping the clutch at over 4000 RPM nad or trans brake launching. This will give you direct locked axle shafts for total posi lock-up

If your going to race and continue racing AXLE upgrade would and should be on the list of items as the stock 12 bolt 30 spline TAPERED axles tend to snap under high shock loads. Right behind the 30 spline end. Might even want to think about c-clip elim kit too if your racing habits become stronger ....
Aftermarket yukon axles or Nitro gear Alloy axles are 229.00 35-40% stronger than your stockers easy.