I would love to do that except not get ripped off
Will that Posi linked by another member work for me I’ll order nowI answered your question the other day. It looks to be a stock El Camino GM 7.5" 10 bolt. Pretty much all the G-body rear ends are the same, except for the few that came with 8.5"s (which yours is not). You really don't need any more information than that to order parts for it. If you just want to put a posi in it, you can go to Yukon gear's site, put your Elco's information in and it'll tell you all that you'll need. To put a posi in, you need the limited slip differential itself, a master install kit with bearings, and probably a ring and pinion while you're in there. Maybe put a set of Moser axles in it while you're at it through Summit racing too. Working on rear ends is a bit of a black magic though and based off your comments you may want to take it to a diff and transmission shop to do it correctly.