Will a 1997 model inter change with a 1999, I have a 1999 that I'm installing headers on and my 1997 is already reprogrammed, and I could swap them????????????

Were's Dustin when you need him, I think they might be the same, as long as the 97 is not the mefi2, but don't go off me!!!If they are both MEFI1 they should work
good luck
Mark

Your 97 will be a MEFI1. The 99 may be an MEFI3. (There is no MEFI2 on the BB Mag motors.) If the wiring harness plugs into the ends of the module, it's an MEFI1. If the plugs are turned at right angles to one side of the module, it's an MEFI3. There is a way to make the MEFI 3 chip work on an MEFI1 motor. Dustin can tell you how.

ttt, where are you Dustin, I need some help, does whipple do a better program than AZ speed & Marine, how much does he charge

Ric232, are you sure about the MEFI2. Last year when Dustin reprogramed my 97 502MPI, I thought he said that it was a MEFI2, but now I'm not sure. I think with enough time and money anything can be made to work.
Dustin will definitely know the answer!!!!!!!!!!!

ttt

If one , the older one has a plug on each end and the other is the newer with the two plugs on the side then no they are not pin for pin compatable and require a change to the wireing harness