shannon

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

4L60bliss

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

shannon

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

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

ronterry

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

JERRYWHO

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

ronterry

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

The order link isn't working for me.

Ron

4L60bliss

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.

shannon

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

2Cool5261

OK I’m running into the same deal I have found out by rebuilding mine what I mean by that is putting new bearings in this particular rear end was put in an Camaro Firebird iRock this is an Australian made rear end which is beefier than the American made one by Borg Warner this company in Australia had a contract along with Borg warner to build the rear ends I guess Borg Warner felt their product was better and bought them out but didn’t use their carrier this rear and looks half Ford half GM the way the axles come out it is a good rear end it’ll handle a little over 400 horses and a lot more torque than the Borg Warner rear and that’s about all I’ve found out so far I’m having a hard time finding bearings I have joined a Australian Hot Rod group on Facebook and soon as they except me I’m hoping I can find more about it it’s the mystery reader and I hope this helps and as I find out more I’ll let you know I’ve got a call into Borg Warner hopefully they’ll call me back

2Cool5261

You’re right about the the year. But not manufacture you bust that open and take it apart all the bearings are made in Australia the carrier has an Australian patent number the Australian bearings can’t be cross referenced at any parts store or GM for new bearings I went to business today and I was able to find some but can’t find the axle seals the Borg Warner bearings are a little smaller and not as beefy as the Australian rear end

vetteoz

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