NB & NCII V8 Fairlanes
Join Date: Feb 2001
Location: Bibra Lake Western Australia
The 85 E uses a separate computer module while later cars have the transmission and engine modules combined. To go to a later transmission you will need to swap the wiring harness and the computer modules as well and choose one that it is compatible with your existing engine and fuel injection system. There are other parts that are week in the 85 E (the clutch pack drum) but a good trans expert will know what they and can upgrade the internal parts for you. However if you just put in 4 litre and matching ECU you should already have all you need for the later trans (get one that was avaialble with your new engine).