Alright well having searched a bit I could only find the specs for each cam but no threads on an actual swap. The 96 cams are more aggressive but is swapping them worthwhile? What gains? Any forseeable problems? Cost?
well they would prob offer minimal gains just swapped stright up. However from what I head if you have adjustable came gears and have them degreed then yes the gains can be quite well.
You won't see big gains since the 99-01 cams aren't as bad as the 03-04 mach/cobra cams. Check on the mach1registry for write ups on how to swap intake cams.
degreed properly, 96-98 cobra cams can make a nice gain for the price at which you can get them for. 200 bux and some sweat for a 15-20 hp gain is worth IMO.