what rearend to go with - Third Generation F-Body Message Boards

ThreeOhFive · 11-05-2009, 01:03 PM

we are still getting everything together for our t5 swap and the 2.73 is getting tossed out. we were thinking about putting a 3.08 in but traction has always been an issue on this car and i think it would be best to go with a posi. now, it has a 305tbi and its staying that way. what gear is going to be nice and jerky under full throttle, but still mantains gas mileage (20+mpg highway). and we need a rear end that will not make the tires stick out in the back. he's going for a stock thirdgen look.

big gear head · 11-05-2009, 01:59 PM

If this is a '90 to '92 car then it will have 28 spline axles. I would use a new Eaton Posi and 3.42 gears. If it's an older car with 26 spline axles then I would also upgrade to the 28 spline axles.

ThreeOhFive · 11-05-2009, 02:12 PM

Quote:

Originally Posted by big gear head

If this is a '90 to '92 car then it will have 28 spline axles. I would use a new Eaton Posi and 3.42 gears. If it's an older car with 26 spline axles then I would also upgrade to the 28 spline axles.

its a 92. it is getting a t5, nothing fancy, an eaton unit would be pretty expensive though right? i dont think he is going to want to spend more than $500 on a rear end...

big gear head · 11-05-2009, 02:21 PM

The Eaton is $440 and set of 3.42 gears is $170. The installation kit is $96. Are you wanting to install a complete rear end or modify the rear end that you have? Any complete rear end that you find is going to have an Auburn or Governor Lock in it. I wouldn't give a dime for either one of these in a performance car. If you want a Torsen unit then you are going to have to go with a 4th gen rear end, which you already said you don't want. The Eaton is the best option. If you go below the 3.08 gear you are going to have to change the differential anyway, unless you get the thick gears.

ThreeOhFive · 11-05-2009, 02:24 PM

is there anyway you could just change the center section? he's keeping the drum brakes on it. could you just swap in a 3.08 center section? what would u need to change with that?

big gear head · 11-05-2009, 02:32 PM

Any gear change is going to require setting up the gears. That means that the pinion depth, bearing preload and backlash are all going to have to be set again. If you put in the parts for a 3.08 you will be changing the pinion gear, ring gear and differential. The differential for the 2.73 gears will also work with the 3.08 gears, but I'm assuming that you want to go to a limited slip (posi) differential at the same time.