Both are 10 bolts. I've never seen one look like the second one.

<img src="http://members.cisdi.com/~anesthes/rear/oldrear.jpg">
<img src="http://members.cisdi.com/~anesthes/rear/newrear.jpg">

 

c'mon mang..

 

I don't know......my 10 bolt looks different than both of those. I guess I should say I have the 8.5" 10 bolt.

 

Is one a Dana?

 

I dont think so.. It's a 10 bolt. Looks to be 7.5/7.6", or at least, 7.5/7.62 cover bolts on.

The carrier says "patent # blah blah, copyright 1987". It seems to be an auburn carrier. The gears say "11/41 GM7 3.73 (M)"..

The brakes are PBR, says "made in austrailia" on them, like on the 9 bolts. I tried using ebrake cables for a 9bolt, and they wont fit over the arm on the caliper. So I gotta figure out ebrake cables.. It's really a mystery rear end..

The housing itself has a GM stamp on the top, with a weird number I can't make out, but the bottom doesnt have any GM stamping like the other 10 bolts i've seen.

At first I thought it was a 4th gen housing, but it measures out 62" from flange to flange..


-- Joe

 

Those same PBR brakes were used on 10 bolts. The rear-end selection didn't change anything to do with the brakes.

 

I know which leads me to believe its a 90-92 rear end, I'm just wondering why the casting is different than any 10 bolt I've ever seen..

It's kinda weird.

-- Joe

 

but gm didn't produce a camaro or firebird with 3.73 gears after 86 according to this web sites tech data section.

 

Just because GM didn't do it at the factory doesn't mean someone else didn't do it later.

 

I don't see why anyone would use old stock rear end gears unless they were on a super small budget. I'm on a tight budget but the cheaping out on rear end gears just doesn't seem smart or safe. If you blow the rear end on the track, you put yourself in a bad position. I've heard of guys slamming into walls because of it. Unless you know were I can get brand new set of 3.73 ring and pinion gears form gm for less than a set of richmond gears.

 

They had a casting change and went to 304 Chinesium.

 

GM had more then one source for castings and they came from two different foundries with some minor external pattern differences. Happens all the time with different sources. No big deal.