1965 904A modification.

Just to give you a number:
I spent around 490$ just on parts for my transmission rebuilt - total stock - no performance parts, just a deeper oilpan. The 904 universal crap rebuilt kit contained mostly wrong parts. Apart from professional cleaning of transmission parts, I rebuild the transmission all by myself. A good converter won't cost much more and should last. If you want to make it right, take your time and don't save on transmission overhaul and converter.