Just a quick question when buying headers for my mach. Looking on jegs they only have them applicable for cobras and gts. I'm assuming I need the headers for a cobra since they're both 4v or will either work. Thanks in advance

 

The Cobra ones are what you want, the GT ones will not work. And get 1-5/8" unless you plan on forced induction down the line.

 

Since the Cobra and Mach 1 share the exact same 4V heads, get the ones for the Cobra, like was stated above, and you'll be good to go.