Beefing Up 904

This is the best advice EVER! So go ask around your area for a competent trans shop for older cars. Try the drag racers first, they know people.
Scrap it and put in a 727.

On the TCI thing I have never spent any money on TCI anything but see a couple of their converters available for what seems like a decent price, compared to a stock reman. How are their converters? Decent or crap?

My converter seems to work ok driving, but I think that my ring gear has issues listening to how it spins over on the starter. I'll know when I swap engines. (That will be happening no matter what)
One of those "as long as it will be exposed and staring me in the face" kind of things.