You will need to shorten the drive shaft . Run a t v cable for shifts , and run a wire for the lock up converter. You can get a KIt on ebay for $15 it works you don'y need to spend more. !984 700s have issues. the accumulator pistons,roller clutch and sprag were all updated by 1987 the pump is a 7 vane and the input shaft is smaller diameter.Change all this and you have the start of a good trans. The tail shaft housing on 700s sometimes come with a boss for a trans mount if you find one Your cross member can be moved back to the holes already in your frame drilled at the factory for 400 trans. It really is very easy conversion with a little research.