99 gt into an 04 mach 1

what would it take to add the intake from the mach 1 into a regular 99 gt??? and would it be easy to do?

Its not possible. The GT has a sohc engine whereas the Mach 1 has a dohc engine.

classic design concepts made the mach1 shaker kit, and they make a shaker kit for GT's.

I think we're getting terms confused here. "Intake" to most of us with V-8 engines means intake manifold. In that case the "Bullitt" intake is your best choice.

If you mean the "hoodscoop" or air inlet, then as boosted said, contact cdc