I just purchased what I believe to be a 3rd gen F-body posi/disc rearend. I know they arent the beefiest pieces in the world, but it should serve the purpose I want it to.......just a way cool cruiser. P/N 10040660.....on a tag bolted to the cover. ratio....2.77....also on the tag ser. #...10983...also on the tag. 0578-026901 731..........cast on the top of the housing. This is a control arm / coil spring setup with what appears to be a panhard bar. It measures 62" from wheel mount surface to wheel mount surface. What is throwing me is the 9 bolt hole covers. I can't find anything in the Summit catalogue diagrams that match up with this. Even the 7.5's appear to have 10 bolt holes for the cover. Thanks for any help. Shannon

Its a 1986 Borg Warner 9-bolt rear end w/ 2.77 gears and Limited Slip.

Bliss,

Thanks for the quick reply.
Am I correct that this is a 3rd gen F-body rear, and could you possibly know the year?
What am I looking for (8.25, 8.5, 7.5,.....GM 10 bolt) when I go to purchase a ring and pinion and internals for this rearend?

Thanks again.
Shannon

great......did some more digging and searching on this site.
Found the www.9-bolt.com site. Came back here and did some more searching and digging on this site.
Now realize I toted home nothing more than a money pit.....how depressing.
I was counting on putting about $800. into my 10-bolt to put in a posi, 3.42s, and disc brakes.
I bought this 9-bolt today for $125 w/ 2.77 thinking a simple gear change would have me going for MUCH less than the 10-bolt.

Anyone in the market for a 9-bolt posi complete w/ calipers, rotors, etc?

Shannon

Your right 'shannon', the 9 bolt is great but the parts are bit pricier. Technically I think it's a 7.75", but Richmond doesn't offer gear sets for it. It's not in the economical interest, since it was in a very limited production.

The 10 bolt can hold up to modest torque, and the parts are much much cheaper.

I wish I could get a 2nd gen 8.5" in one of these 3rd gen, but all the mounting hardware makes it hard on the pocket book.

You can get heavy-duty rear ends, like the Ford 9", or GM 12 bolt with the correct axle length, & mounting hardware from a company called Moser, BUT <hehe> they'll set you back about 2 grand...

Ron
Hoping my 10bolt will hold to some road racing with 425FPT

The 8.5 10 is less than a 12 bolt.

Try this link http://www.amazingmechanical.com/rearend.htm

I don't know how i found the link....

Jerry

Cool, hey Jerry did you catch the price of the 10bolt 8.5" ?

The order link isn't working for me.

Ron

Like I said, its a 1986 Borg Warner, so it was used during the '86 Model Year.
Its a 7.75" ring gear, but like you already found out, Richmond doesn't make replacements for them.

thanks Bliss......color me stupid.
Shannon