I have the 1991 LO3 powered camaro. I am going to get a posi out of a 4th gen firebird tomorrow along with the gears. Do they really make a difference in how fast your car is my my car's driveline? Are 3.42 gears too much for the power of my car? Also, does my car have 28 spline axles or a 3 series carrier? Last Q, does anyone have a good tech article or install guide online for this swap? Thanks guys, i'm a newbie to the differential area and the searchs i find are broken up and I can't figure my answers out. Thanks.

 

you'd have to look to know what carrier you have, it should be 28 spline. you ought to be able to find all you need to know here or in a repair manaul.

 

I have basically the same car as you, and I did basically the same thing you're doing. But I bought the TO posi from SLP. If it's stock, you have a 2 series carrier (2.73). 3.42 gears are fine, but you will also have to swap speedometer gears if you want your speedo to be accurate. It's not rocket science, but you will need some specialty tools to make sure the backlash and pinion depth are right. I used a video made by Richmond to do my swap. JEGS sells it.

You will definitely like the 3.42s and posi compared to what you have now. But the *** end can get a little squirrely if you punch it going around corners and it's rainy or slick. Both tires will break free with the posi, whereas only one would with the stock open diff.