I have never heard of such a combo, but I think thats what was in my car. 88 SC convert. It may be changed from original. The tags are not on the cover. Anyhow, I want to go 3.43 or 3.73. Anyone with input as far as, what is my combo, and whats a good way to change ratio's. I want to keep my limited slip (maybe posi). I haven't opened it up yet, just by turning axles and input shaft we figured this out. If someone added posi, why would they leave 2.73 in it??

 

A common set-up on 305 TPI cars with a automatic. I had that set-up on my 87 IROC.

 

My 87 came stock with the 2.73's LS. and yes it doesnt pull for crap! thats why Im in the process of changing my rear end to 3.42's

 

Thats still a 2 series carrier though right? So I need to change the carrier and the gears, but I still keep the LS?

 

Richmond Gears offers gears in 3.08, 3.42, and 3.73 that will bolt right to your 2 series posi carrier. They seem to be priced around 200 bucks. Then add the cost of install, unless you can do it yourself.

It may be cheaper to just find a complete rear end with a 3.42 and posi.