hey everyone, i been restoring my 92 trans am for the past few years and now i'm to the rearend. it came stock with 2.73 gears and they have got to go! i was for the longest going to buy a used axle with 3.42's and go with that, but now i have found a really good deal on a 10 bolt out of a 3rd gen with 3.73's. now i'm having a hard time trying to guess what gears to run. my car has the tpi 305 f engine code stock cam with a few mods like headers, cat back exhaust, under drive pulleys, chip, and ported intake with cold air box. trans is a stock 700r4 with a little shift kit. so, what do you guys think would be the best gear. oh.. the car is by no means a everyday driver or will it be.

 

Gonna keep it TPI? 3.42.

Gonna change the intake and go with a higher revving setup like a Mini-Ram and cam? 3.73.

 

thanks for the reply.. going to keep the tpi for now. i think the 3.42's will be best as well, but was not sure. i found some older post on here where people had the same mods almost as me running 3.73's but with 350's. did not know how the little 305 would do?

 

For a long tube runner stock style TPI system 3.42 gears are really all thats needed. That gear ratio combined with the 700r4's low first and second gear ratios are all that you really need.

From the factory 3.42 (10bolt) gears and 3.45 (borg warner 9bolt) gears are the lowest gears that GM installed in TPI cars and only with the LB9's.

The L98's got 2.77 gears (borg warner 9bolt), 3.27gears (borg warner 9bolt), or 3.23 gears (10bolt). The L98's had more torque than the LB9's so they didn't need as much rear gear to perform.

I'm in the process now of getting the parts together to rebuild my rear end. I'm going to switch from 2.77 gears to 3.27 gears.

TPI is a low and midrange horsepower and torque system by design. 3.73's would be better if you had a mini-ram or LT1 style intake system. 3.73's would be a better match for those kind of short runner intakes that perform best at upper mid-range and high rpm ranges.

 

thanks for the reply yaj15. 3.42's it will be. you really know your stuff!

 

Ha ha thanks. Believe me there are some areas that I am blind as a bat in lol. I've just learned by experience and reading info from this site over the years.

 

Will the 9th injector give the L98 a no start if its not working?

 

You know your stuff and i need help figuring out my all crank no start issue on my GTA

 

You might get a better response by posting in the General or the TPI forum instead of the Transmission & Rear End one.

 

When I rebuilt my borg warner rear I put 3.73's and I aslo have a shift kit in the 700r4. Needless to say pretty fun driving around town. Noticed a little higher rpm on highway but nothing to bad.

 

I have a 3:42 ring and pinion for a 10 bolt.