Without getting into the "why do you want to do that", a TH350 can bolt in place of a 2004R. That is if it is a BOP pattern bellhousing and a short tailhousing transmission.
If you have enough parts it's a direct bolt in and the drive shaft swaps right over but the TH350's has it's own dip stick/tube and uses it's own cross member, the 200-4r's won't work. Add a vacuum source to the modulator valve and done.