Looks like I finally found the correct replacement trans for my 64 Valiant /6-225 convert, (a 904 with push button shifter). I also located a good source for a rebuild kit that will include the extension housing seal for the rear yoke, which is a bolt-on (Fatsco Transmission Parts in Farifield, NJ Fatsco.com ). Not necessarily the cheapest but at least complete and correct.

Thanks to Charlie_S and Doc, both of whom were very helpful. If I can help anyone else with a similar issue feel free to contact me, now that I'm (semi) educated. I'll make sure to limit my input to what I know and be certain to be clear about what I don't.

Kevin
Raleigh, NC

I am thinking 62 thru 65 is the general range of years but the valvebody in the 65 has one extra detent for the column / floorshifters. (no pushbuttons in 65) A 65 904 could be used if the 64's valvebody was swapped into it.
DD

I went through this a while back with my '64, and the message traffic should still be on the old board. Thanks to Doc and the guys here, the car is back on the road and I'm still mostly sane.
It took me three "new" transmissions, a lot of time, and a lot of unnecessary aggravation to get it right, but it hasn't given me any problems since.
Lessons learned/reinforced, in no particular order:
You need a factory service manual.
Applications books are not always right.
Rebuilds don't always work.
Keep your torque converter and flex plate.
Keep all receipts and watch out for deadlines.
When it comes in, install it and test soon thereafter.
Use Doc's method for adjusting the shift cable. Messy, but it works!
Just because you worked on it last, doesn't mean you messed it up.

Oh, yeah. one more: Ebay photos don't show you everything you need to know ...