I have an 84 mustang with a 3.8L I am buying a 86 Mercury Grand Marquis which a 5.0L engine. I would like to swap in the 5L. Problems that I have are not very much knowlege on this. The Mercury has an auto with od. Would that tranny fit?? Can I use my old one?? Also the Merc. is fuel injected so would that computer work in the Mustang??