Looking to Add a LSD/Posi to my Classic Car…

I’ve got a 1986 Chevrolet Caprice Brougham that I’m restoring. The differential is leaking badly and the shop told me that they would install a LSD/Posi for free given I provide the part.

The problem is that I’m having trouble finding a LSD/Posi for my gear ratio which is a 2.56. Aside from this I plan on leaving the car as original as possible, so maybe I’m searching in the wrong places? I haven’t had any luck finding it and I really don’t want to go up to a 3.xx gear ratio, but that may be my only option. Should I keep looking or suck it up and change the gear ratio?

If anyone knows anywhere I should check, do let me know. My differential is a 7.5" 10 Bolt 26 Spline w/ 2.56 gear ratio

  • Every_Lead3128@alien.topBEnglish
    1·
    11 months ago

    They probably never made an lsd in that gear ratio. You’ll most likely have to go to like a 3.07 rear gear or maybe even a 3.25 to get one

  • NewrytStarcommander@alien.topBEnglish
    1·
    11 months ago

    I didn’t believe you but checked a couple of catalogs and the aftermarket limited slips for 7.5s all say fit 3.23 and up only. I assume it has to do with the size of the ring gear being too small on the 2.56 to fit the carrier. Unless GM ever made a limited slip for a 2.56 (unlikely) then I think your choices are stay with the peg leg, or go to a 3.23. Unless your intended use is days at a time on the highway at 80 mph I’d put a 3.23 in it- that dog of a 5.0 needs all the help it can get, and will be a bit nicer around town and what not with a 3.23.