Originally posted by N20D5OH
Not minor variations at all. The Mach 1 motor is basically an '03 Cobra motor minus the blower and the forged internals. The heads and cams are completely different from previous year 4V's. I'm looking for a little bolt on HP for mine as we speak. 
Heads are not much different from a 99/01 Cobra. Just bigger exhaust ports. They are very different from the 96-98 Cobras though.