Recommend a Transmission

[Bandit]

I suggest swapping to a manual gearbox!! Unless you have to have an auto for some reason.? it is pretty simple doing the conversion if you go through a company like Keisler or Classic 5-spd. I did the entire swap in my 80 TA by myself in a few days, it was straightforward (and I am by no means a mechanic).
I had been dead-set on going with a 700r-4 (cheaper), then I changed my mind to 4L80E (stronger), but once I started pricing everything out, i.e., electronic controller, hd torque converter, etc, I realized I could convert to a Tremec TKO-600 for the same money. Now I can be in whatever gear I want, have a bulletproof tranny, and an extra gear over the OD autos.

Here's the links in case you're interested in going this route.

http://keislerauto.com/gm/chevelle-gen2-kits.html
www.classicchevy5speed.com

If you absolutely must have an auto, check out this link:
http://www.transmissioncenter.net/4L80E.htm

This is the 4L80E I was going to use, it is an absolute beast!