I have a 94 tbird with the 4.6. and want to swap in a pi mustang motor. Do I need to swap computers? And what wiring is involved

 

Well, I didn't change the EEC when I did a PI swap in my mustang but I don't know how the T-bird's EEC differs from the mustang. The only real difference (as long as you have a complete Pi engine and not just the head, intake swap) is trying to find a place to put your 2nd coolant sensor.