5.7 swap questions?

I thought this whole time that the gauges would be the hardest part. what about the mph gauge. Is the performance that much better with the carb setup? I want a street cruiser, so i wont be adding a giant cam. i want to run the keisler TKO600 5 speed tranny. If you dont mind me asking, how much would i have invested in a mild build, and what was your cost for the engine setup thus far? thanks, youre a big help