I am kicking around my winter project and gonna go 4 valve in the 02 gt. I have researched the options and differences between the Aviator and mark VIII swaps. Trying to get other opinions on it. Looks like the late 05 Aviator with mach or cobra intake would be the easiest and most cost effective way to go. sounds like the heads and internals are pretty decent. From what I can see after getting a mark VIII and getting heads, cams ect. for it would be cheaper to spend some extra $ for the newer motor in the Aviator. I know the Aviator has a cast iron block but its basically a Terminator motor.