Need a reliable trans that will last

With the right parts (and the depth of your pockets) I know of a 904 that lived behind a 1200 HP, Steve Schmidt engine. My ex-boss runs a BA/A Pontiac that has run in the high 6's at a hair over 200MPH. That of course is on the extreme end, however,
If you want to see what parts his company makes for the 904 and other series of High Performance transmission check out the website www.tcsproducts.com

They sell to most of the major performance transmission builders.