Looks like someone put a 9 bolt with 2.77's in my IROC and i'm getting bored of my car's performance so looking to upgrade to 3.73's, but having a hard time finding gear sets for the Borg Warner 9 bolt's, anybody know a good source? Im thinkin maybe this is also why the 99 Cobra 5spd i drove today feels faster than my IROC even tho I am about the same if not a few tenths quicker in the 1/4. So any suggestions on locating a gear would be appreciated. Also what kinda price should I expect on labor to have them installed? Thanks guys. Might be time for a supercharger... but I need to hold back until my 383 project is done Once the race car is running I can start worrying about daily driver hp lol.

Oh and just to avoid any confusion, I am not looking for a reccomendation on gear ratio's, this car will no longer be seeing any track time, just need to know where to buy em

 

there are very few gears offered for that axle, as I recall you can get a 3.70 ratio and a 3.42 and a 3.27 I changed out the whole axle so I could get a 4.10 set.. DTS drivetrain can get you the gears http://www.drivetrainspecialists.com/


ps. got pictures of that cage installed

 

www.9bolt.com

 

Only gears for a 9-bolt are 2:77, 3:27.3:45 and 3:73 and all avaiable at 9-bolt.com. The SOTP feel in a fast car seems to slow down after a while. I guess its being used to it, I have the same feeling.

 

They've got 3.70's and 4.10's for a 9-bolt...

 

greezemonkey: cage pics are on www.zee28.com - not goin with the tunnel ram setup tho, changing to super victor and demon 850 carb and a custom solid roller turning 8k.

Thanks for the info guys, i'm actually kind of tempted to put the old rear from the 84 Z into my IROC, its a 10 bolt with a powertrax locker and 3.23's but the whole locker thing bugs me since i want handling on my daily driver. It really pissed me off when one of my friends happened to notice that the rear was a 9 bolt and the tag said 2.77, it explained why my RPM's are so low lol, I always assumed I had 3.23's.

 

OK Holy ****, $425 for the gears and $385 labor to install??? I THINK NOT! Looks like I'm stuck with stupid 2.77's.

 

just keep an eye out good used 9-bolts can be found. I got mine with 3.45 complete from caliper to caliper, with the praing brake cables for $250. I think there are a VERY few 3.73 9-bolts. good luck.

 

There were never any 3.73 9-bolts. 3.73 is an aftermarket gear for that rear. They were 3.70 and AFAIK, only offered in 1985 Trans Am 5spds. Nonetheless they are rare. Try emailing places like
www.hawksthirdgenparts.com
www.thirdgenresource.com
Etc.

They usually get some nice stuff.

 

I wouldn't mind even a 10 bolt, the fact I have a 9 bolt is just a because some idiot probably blew the rear end out n put in what he could get, I mean, I had an RS grille and front clip for gods sake LOL yeah that grille got changed out real fast. i'm no longer running nitrous on the car since i can't afford to be without a car and I noticed I cracked a piston when i rebuilt the motor after bending a rod thanks to a flooded road drowning my motor, so trying to turn this into my "reliable" car that I told everyone i'd stop spending money on, but hey if 3.73 gears stops me from buying a brand new car altogether then i say its worth it lol.

 

That what I was thinking 3.70 . Thanks for the clearification.

 

Yeah, a 10-bolt will stand up to your mid 13 second car just fine. Rebuild it with a support cover, 28 spline axles (if you don't already have them), weld the axles tubes, etc.

-Corey

 

OK here's the big question - is swapping the disc brakes from a 9 bolt onto a drum brake 10 bolt rear do-able? What is involved? I have a 3.23 drum rear with a locker sitting here pending to be replaced with a Ford 9" and I know someone selling the rear i want with auburn posi but its drum for $300, if my brakes will swap then i'm willing to do it but i don't want to downgrade to drum, cuz i hate drum, lol.

 

I know you'll need 10-bolt backing plates and e-brake cables. I really don't know how do-able this is though. Hopefully ebmiller88 will see this post, he's a brake genius.

If I were you, I'd look for LS1 style rears. They can be had for ~$150 and are....huge There is a tech article on swapping drums->LS1 on TGO.

www.ThirdGen.Org

 

If the 4th gen rears weren't wider than the 3rd gen's i would love to but i don't wanna buy 4th gen wheels ..... or do I? lol no... bad mike bad... im trying to avoid looking at spohn torque arms too... cuz i hate working with that stupid stupid tail mounted poly bushing.