e30 325i motor build

hey guys. i have a little issue regarding my motor conversion. heres the deal. i have a 85 pre facelift 320i i have got a pre face lift 320i motor to go in. the current gearbox is a getrag 240 and doesnot have the holes for the flywheel sensors. is it possible to replace the ecu and loom with a face lift one. replace front pully. run a crank sensor off the front pully and use my dissy from my 320i on the side of the block? are there any major issues regarding this theory?
responce greatly apreciated. many thanks. oli