I coulda swore I had a 7.5 10 bolt. After re-checking last nite, I got the 3.27 9-bolt. What the heck am I supposed to do with this overpriced junk? I want 4.10s, but I'm not going to spend an arm n a leg for them. No way to swap out the carrier or anything? It's in an 87 IROC-Z. 1.8 60's stink!

 

I think another member on here had posted a link to a source for some reasonably priced gears for the 9 bolt. Like $170, about the same as 10 bolt stuff. Scroll and find that, it was recent, I don't remember the site it was at though.
Why can't you swap out the carrier?

 

they make 3.70 gears for around $170-180....which is not bad until you price in the install kit which is another $160. So I have to decide do I want to spend $350 plus labor to put in some 3.70 gears instead of the 3.27 I have now or do I want to save for a 9" and know I won't break that instead.

 

The cheapest route to 4.10 gears is to simply find a 10 bolt rear to replace the nine bolt with. If you have about $2k to spare, I guess you could pick up a custom 9" or a custom Moser 12 bolt. When sticking with a stock rear, I'd much rather have a 10 bolt since the parts are a lot cheaper and available everywhere. The nine bolt may be marginally stronger, but the hassle of locating parts, the expense of them, and the fact that the only aftermarket ratio available is 3.70 makes them obsolete in my book. If you ever burn up the posi, which happens all the time, they're even more impossible to find new than the gears or other parts.

 

3.70+ gears are too much for an L98 TPI anyway.

and my install kit was only 120 bucks from reider racing. cheapest i seen gears and install kit was 299 from Reider

 

Don't assume that's what its for. I now have a nice lil 383 stroker motor w/ a 3500 stall behind it.
I'm looking for a 10 bolt rear that I can throw my gears in. Any idea what cars are more likely to have a 10 bolt disc rear?

 

The best thirdgen cars to find a 10 bolt posi/disc rear from are any Z/28 or GTA between the years 90-92. These cars usually got the ten bolt with posi and the better pbr aluminum calipers. These years also got the stronger 28 spline axles as well. If you don't mind the rear wheels sticking out another 2" on each side, 4th gen 10 bolt posi/disc rears are even easier to come by. I snagged a 3.23 10 bolt posi/disc for my car out of a 91 GTA.

 

good thats exactly what i was hoppin you would be saying...update ur sig and profile lol i hope it does rev to 5500 cuz those gears will get u up there! but in all seriousness...you should get a 12 bolt or 9 inch

but up untill 98 the 10 bolts had auburn clutch type posi's (from what i read) and the 99 up had zexel torsen units. advantage torsen because clutch type posi's wear out somewhat quickly compared to a torsen. torsens lock up great for good posi action too!

 

I havent been able to find a pic of a 4th gen rear with Iroc wheels on it. Dunno if i like the idea of it sticking out that far.

 

i got quite a few...all in here

https://www.thirdgen.org/forums/tran...-gen-rear.html

 

will the pbr aluminum calipers replace the old heavy ones with out any modification? i have to get new calipers for my rearend so ill look for those at the parts store. you said most all 90-92 cars came with them?

 

yeah my 89 has them.. so 90-92 should definately have them...but 93-97 LT1cars have the same stuff as well.

 

You'll also need the pbr backing plates since they're different from the iron caliper ones, but they're quite easy to come by most of the time. Any of the ten bolt disc rears from 89-92 will have the right ones. There's a guy on ebay right now that has a brand new, fully loaded pair of pbr rear calipers listed with a starting bid of $149, which is not a bad price at all since they're brand new AC Delco ones. If you got these, the only other thing you would need is the backing plates. The auction# is 170041877484. Or you could contact Ebmiller88 on the boards here. He has all sorts of brake stuff for our cars, and would probably give you an even better price for all the stuff you'll need, including the backing plates, lines, etc.

 

Will the disc brakes off of my 9 bolt swap to a 10 bolt? All i could find at the boneyard are drum rears

 

Technically, you can make the 9 bolt parts fit. All you have to do is router out the holes in the backing plates a little. The holes on the axle housing flanges have slightly different spacing, but it's not much. I helped a buddy of mine do just the opposite. We managed to put his 10 bolt stuff on a 9 bolt rear by just routering the holes a bit. Hey, I just noticed Bowtye101 is selling the backing plates you need in the classifieds for $40.