I'm doing 6.1 swap now, same cost for swap other than the extra cost of a 6.1... let me say first hand, it's not cheap! There's probably as much money in swap parts as the 6.1 costs.

If I were doing a 5.7 swap into a truck, I'd use the dash and as much as I could from a donor vehicle. The computer/wiring is a big cost part of the swap.