RE: got the hemi....need a transmission
Actually, original trans were:
727 for Automatics (the 904 is auto for small block)
A-833 4spd of which only the 18 spline input shaft was used on 440 & Hemi as opposed to the smaller 23 spline for 383, etc. You can still find 18 spline A 833's but not cheap, but cheaper than Keisler, so it all depends on what you want to do.
Finally, a big question is what rear end gear you're planning to run? If over 3:54 (ie. 3:91 or 4:10) you may want to go w/ the 5 speed for driveability on highway. 3:23, 3:55 or 3:54 in a 4spd is quite liveable.
Good luck