At that power level I'd stick with the Torqueflite or something more modern. The cost of a new beefed up Powerglide and modifications to drop it in will be twice that of the Torqueflite. It would be total overkill. That and you only have two gears. Great for a bracket car, but not so much for any kind of street machine. Might as well kiss any kind of fuel economy goodbye too.
On the manual front, a Tremec T56 or TR6060 would handle that power, especially if modified. Not too many other streetable manual transmissions besides that could handle that power reliably, even the TKO-600.
On the auto front, there are many auto transmissions with O/D that could be made to handle it both streetably and reliably. It really depends what you are looking for, how much work you want to do to get it in, and what you want to spend.
