Ecm
Reply #1 –
Look for a DA-1 Mustang ECM. I see them from time to time here and Ebay. Others are available. $50 or so.
If you go with a "bigger than H.O" performance cam, you MAY need togo to Mass Air. If you are using an H.O cam, yeah, swap in the Mark VII ECM or a Speed Density Stang cam. All Mark VII's were speed density.