I just spoke with Sean at Dynamic Converters. They built the 42RH that is going in my 65 Dart wagon. Anyway they will be rebuilding my 64 904 to include beefing it up where necessary and new drums, pump etc to take a later converter. They will also build a new 9.5 inch converter of about a 3000 stall at the same time
IDK about a rebuild kit per se for the push button 904 like the one I have. You might give them a call or I can check for you when wife and I drop my transmission off next week