Hot Rods Can Anyone ID This 10 Bolt Rearend?

So I bought a raunchy 1938 Chevy coupe and it has a 10 bolt GM rearend in it. I don't have it home yet to look any further. The rearend cover is smooth..doesn't have the eyebrow or mustache mark the early 8.2 10 bolts have. What has me stumped are the axle tubes. For the last 6 to 8 inches or so..they neck down. Hoping it's not a 7.5"...the cover seems to be 8.2" or 8.5" in size. Note that at the 1 o'clock bolt on the rearend cover there is a tag. I'm assuming it has a posi or limited slip diff. Haven't been able to find out what cars used this type of 10 bolt. Anybody know? It is a 5 lug axle setup.

 

How do you know it's a GM?

tell us what the tag says, and check the wheel bolt pattern?

 

Hmmm...its not GM...evidently it's a Granada 8.7" weirdo rear..

 

So..I got excited when I looked under my new project '38 and saw a 10 bolt and a tag hanging off a bolt. Thought GM... limited slip or posi. Just one more thing I can sell off this project...to whittle down my investment. The narrowing axle tubes for 8" or so, threw me off as I don't recall GM doing that. After finding out it was a Granada rear...im bummed out because Fords put little tags on the most mundane rearends..listing a gear ratio and some other info...so near scrap value.

 

The tag sure looked like ford to me, as did the necked down axle tubes. Sorry to be the bearer of sad tidings.

 

It happens. I still like to learn new things though. The rear looks totally GM to me at first glance. I guess the 8.7 was the precursor to the 8 8. They don't share any parts though..

 

Just curious. But what is the gear ratio?

I’d guess in the 2.7:1 or so?

 

Most were pretty tall geared. I don't have the car home yet to look into it further..

 

the tag will tell you

 

Yup..dont have it home yet to see..dont think it makes any difference what it is...