On a mach 1, there is quite a bit involved.
You can find all of the parts, eaton, manifold, brackets, intake, injectors, etc. for probably about 2K. You'll have to do some fab work to get some of the parts to fit, but, for the most part, it's a "fairly" smooth swap.
You can expect 400-440 RWHP, 400 TQ on a stock pulley.
If you check CMC, a member named Drenath has an eaton swapped Mach and it's one hell of a quick car. Not sure if Pete is a member here.