OK, I think it's time to upgrade by gears! I have to drop the tank to change the fuel pump and this will be the perfect time to upgrade to a 3.73. posi (since I have to drop the rear end anyways)!

I currently have the stock 3.42 std. gears (non-posi) that came with my 85 IROC.

I hoping to be able to use the same axles, rea end and just change out the guts in the diffirential. I have enough know how to tear it all apart and put it back together, just need some help or suggestions on what parts I need to replace, gear, pinion, etc.??

I am not opposed to keeping the 3.42 either if there is a way to make it posi, limited slip... The car seems to like that ratio too.

 

You'll replace everything but the axles and the housing.

Not exactly a bolt-in, setting up gears requires some measurement and alignment work.

 

if you can find a 26 axle spline posi from a 3.42 or 3.73 rearend it will bolt in and use all your stuff.https://www.thirdgen.org/forums/tran...-10-bolts.html