I did just that... but it wasn't in an A body. I put a 700-R4 into a B-body and spent only $760 - total including the driveshaft. I also didn't have to cut the floor or the torsion bar brace at all. Unfortunately, the A-body is too short to make it work out this easy though :( But, you could probably get away with cutting the front half of the torsion bar brace like they do for the Keisler auto-overdrive conversion.
You can check it out here if you are interested:
