I am looking to put my power to the track. Would putting an aftermarket differential in my 91 GTA be a good decision. I want to get good in town handling out of the car so not really considering posi. I was thinking of going with a 3.42 gear and am wondering if I will have to change carriers. What is the stock gear in my car. I thin 2.73Right now car just blows tires off on starting line. Car has a torque bar running from back of trans to front of rear end. Is this factory of was it put on aftermarket. Thanks in advance for any advise.

 

The torque arm is factory setup. The car needs it to keep the diff from rotating.

An aftermarket diff will either be a 12 bolt or a 9" and either diff complete will cost you around $2000.

There's nothing wrong with your '91 diff except some poor gears. Invest in some aftermarket suspension parts and some better gears. Click on the Spohn banner at the top.

 

How does posi effect handling?

 

it's not so much how it affects handling as it is how bad it is for your rear end. puts everything in a bind when you turn.

 

should I put 342 or 373 in it. Also, will a aftermarket torque arm gain me anything.

 

I think you have a posi and a spool mixed up. Time to do some reading.

 

 

The posi is designed to slip when going around corners. That's why there are clutches in it. A spool or mini spool has no differential action and locks the 2 axles together. This isn't recommended for any street use.

 

A few of my buddies run mini-spools on their fords. Not sure how much different it would be on the GM, hell I've thought about tossing away the 9-bolt for one.. Gears for 9 bolts arn't cheap.

Anyway, they've run them on the street for years with no problems. It squeels a little around the cornor, but it isn't recommended by manufacturers. In California its outright illegal.

There is always the chance of breaking something in the rear end too..

-- Joe