My buddy is sellin me his used third members. He sais they have factory 4:37 gears and that they came out of a 1988 turbo 4cyl, but hes not sure about if they are considered a v6 or 4cyl third members . i need to know soon so i can order my aussie lockers or lockrite lockers. Im stickin to the lunchbox lockers because it fits my budget and the snow is gonna fall soon

 

It is easy to tell a 4- and 6-cyl diff apart by looking at the housing:
http://www.4crawler.com/4x4/4R_TechInfo.shtml#DiffTypes

Or look inside at the carrier, 4-cyl has only two pinion gears, the 6-cyl (or turbo) would have 4 pinions.