Kevin, yes it is a 411 rear end, out of a 3/4 ton chev. truck. Not sure about your 200? rear end, I would have thought maybe 370 for auto trans. But any way you have to do the math. The way I approached this was I knew I wanted somewhere around 60 rpm’s at the chunker end, then worked backwards towards the engine/electric, what ever you choose to drive it. I also wanted to have a slip clutch so I used the belt from the jack shaft method, works very good. The belt was off an old square baler. I made the 4" pulleys on the jack shaft. As for the truck wheel adapter, 1/4" plate, drilled the holes, pressed the wheel studs in, gussets on the back from the original drive shaft to pinion gear (what ever that is called). There is more to it than that so if your bound and determined to do this please ask and I will do my best to help out.
One other thing, anytime one wants to weld cast steal to cast steal cast steal to mild steal, high carbon steal to mild steal, use your buzz box, and low hyd. (7018 rod). It will last forever if you do it right. Wire will work for awhile but will break in no time.