Hey guys, I've been planning on replacing various worn out parts on my 91' Firebird with the 305 tbi and T5 tranny. One item I am certain I'm changing is the rear end (its seen better days). I was thinking of grabbing a rear end out of a Trans Am or some upper model f body (deff thinking about posi tho), would that do any good? I figure while it's out I might as well put some better gears in there. So my main question is, what gears would let me keep some what good gas mileage while giving my bird some more kick? or should I leave the stock gears alone? The only thing performance wise I have done to the car so far is a 3" cat back and I plan on headers at some point, nothing too crazy. Thanks for any help guys.

 

definately if you have the 2.73's in the rear end going up (numerically) to something like a 3.42 or a 3.73 will really wake it up. 3.42's will save a little of your gas mileage and be more streetable. Im in the process of making my 92 RS 305 posi and 3.42 gears. A friend with a car nearly identical has the 3.42's and its a night and day difference from the 2.73. posi will definately keep it planted better.

 

Well, my car has the T5 and the rear is stock so I'm assuming it has the 3.08's. Will the 3.42's still be a good choice? Like I said, I'm going posi for sure. Thanks for the reply ccook, and keep me posted on your car.

 

3.23, 3.27, 3.42, 3.45's. 3.73 for the jack rabbit affect. If you're searching for a complete rear end to swap in with the gears you want, print out the information contained in the attached thread. It'll be of service to you when doing the wrecking yard search.

http://sethirdgen.org/reardata.htm

One thing you dont mention is if drum/disk brake conversion is or is not part of the plan?

Good luck

 

Thanks a ton for the list of codes Wade. They'll be really helpful in my search. I honestly haven't even thought about the drum/ disk conversion, I just assumed it'd be a pain. How hard would that actually be? What other parts would I need to get? Thanks again for the reply/ help.

 

Hi Wade, just read this post of yours. I tried to go to the web page, but it couldn't find it. Do you happen to have a web address that will work for a list of codes for a junk yard search for a complete rear?
Thank you in advance!
Wayne