Transmission cross member needs to be made deeper and moved back. You will need to have your driveshaft shortened (transmission is physically larger all around, and longer). Transmission tunnel needs to be bashed around for clearance. Then you will need a kit to give you control over the lockup convertor and O/D. If you are seriously thinking about this, then you may as well go all the way and get the O/D based on the A727, which is called the A518 or the 46RH (not the 46RE). Only thing with that one is that you should probably think of dropping the rear end gear some (something like a 3.23:1 or a 3.55:1, also a great opportunity to put in a Sure-Grip unit). The O/D A904 (called the A500 or 42RH) is harder to find, and has the same torque handling limitations as the A904. If you are leaving the engine stock, I suppose that point is moot, but there are a lot fewer A500s/42RHs than A518s/46RHs. O/D ratio is the same (.69).
Kostas
P.S. You can get the kit that handles the torque converter lock up and the O/D from PATC.
