89 rear end question

My Caprice is an 89 with the 7.5 rear end with a 2.73 ratio. My question is what spline axle would I have and can I get a 3.73 ring and pinion from an S-10 and install it in my housing both being the 7.5 size if the spline counts are the same? Do I need to swap out the carrier? The reason I ask is I could get all this for free.

The spline counts are the same if you have the same years. I don't know about the 7.5 counts, but on the 8.5, they were 27-spline until 1989 when they went to 30 spline.

You can get the carrier out of the other vehicle and it won't matter what the spline count is, if you reuse your spider gears.

As for "setting it up", can I reuse the shims in the other rear end and just swap it in mine with that carrier and just drive it? Or am I going to have to get marking compound and a dial indicator to set it up? I don't really know how to set it up properly. Or do I reuse my shims and start from there?