this summer im planning on doing a rear end swap on my 91 firebird. im wanting to swap from 2.73's and a 10 bolt to 3.42's and posi 9-bolt. the problem im having is that all i can find is gears for 10 and 12 bolt rear ends. does anyone know a place where i can buy gears for a 9 bolt. do i have to have specific gears for the 9 bolt or will certain 10 bolt gears work. sorry if these questions seem kind of stupid but im new to the whole swapping gears thing and i know even less about the 9 bolts.

 

For your 9 bolt check the link.

http://www.drivetrainspecialists.com...ner/index.html

9 bolt and 10 bolt rear end gear parts arent interchangeable.

 

the only gears that that site has is 3.70's. that might be a little too much for my car. do you know of another site?... thanks for clearing up whether or not i could interchange the parts

 

Try searching the web. That's what I did when I added the link.
When searching look for the Borg Warner 9 bolt.

Good luck

 

If you don't want 3.73's get a used set of stock gears from someone on here.

Most 9 bolt's have 3.23 gear's in them to start which sounds like what you're looking for....
You need 3.23 or higher if you want to swap gear into it anyways as you need the 3 series carrier.

https://www.thirdgen.org/forums/faq-...now-about.html

 

3.23 is not available AT ALL in the 9-bolt. Nor is 3.42.

The majority of them are 2.77 or 3.27. A few, specifically the 305 5-spd cars with G92, got 3.45. A VERY VERY few, specifically 85 Firebirds with L69 motors, got 3.70. There were also a few 3.08s.

There aren't many sources for 9-bolt gears, and the few that there are, usually have only 3.70 or 3.73.

As stated, no parts whatsoever will interchange between the 9-bolt and either kind of 10-bolt or 12-bolt.

To put 3.27 or higher gears in a 9-bolt, you'll need a 3 series carrier. I don't think anybody makes either a ring gear spacer or the "special" thick gears, like you can get for some other models of rears.

 

Oh ya, 3.27... not 3.23.
It will be stamped right on the ring gear.
Some shims are interchangeable, that's about it.

 

just get a rearend out of a v6 car at a junkyard...they had 3.42's...prolly spend less than $100

 

i have a 87 z28 with 2.73 what spline do i need ?? i know i need the "thick" set . hows this ???? http://cgi.ebay.com/ebaymotors/Camar...spagenameZWDVW