12 bolt posi rear
 

Fits 68-72. Factory 3.73 rear now has 5.13 gears. Clean inside. Ready to bolt in and do burnouts or
Swap out the gears. 1500 or b/o plus the ride. Located in upstate NY.

So no chance this fits in a 64 a body?

It fits, just an inch wider overall. All 64-72 A-body rears will interchange.

Bman is correct. It will work

thanks guys. so if its an inch wider - in practical terms my back tires would stick out an inch? and if I understand backspacing correctly (which may not be the case) i would need to get new rims with different backspacing to put tires back to original?

One half inch per side - one inch overall width increase of the rear end assembly.

If you have some room on the outside as in more than 1/2” then your current wheels should work.

thanks b-man. so 1/2 inch on one side is not going to be noticeable I would suspect?

What is the code on the axle and what is the date code?

NF stamped on tube. Looks like K87 date

There should be two letters followed by 4 numbers followed by a single letter stamped into the axle tube. I think a 3.73 rear should be a K5 code for posi and K4 for non.

Sorry, CI stamped on axle tube

It’ll fit in a 64 GTO, took one out of a 70 GTO and put it in my 64 GTO yes about 1” wider. Still was able to get a 11” slick on.

Can you post a picture of the axle code and casting date?

Definately no expert here, but will rear end that takes a 3.73 take a 5.13 gear as well? I thought that a 3 series took the 308 and 373s and 4 series took 4.11s and such. 5 series for the 5.13 and so on.

They make 373s that fit on a 4 series carrier

Okay, Does a 5.13 fit that series?

They are GM gears so I'm going to say yes. They are thick so it might even have a 3 series. I'm sure the experts will correct me if I'm wrong

My '64 with a '68 12 bolt.

It's all about the rim backspacing.

I currently run 245/50/17's, but have run 255/60/15's also.

The 15's were on 15x7's with 4.25" BS. The 17's are on 17x7's with 4.625" BS

Still available