2.5 to 4.2 wiring - is it better to start over?

Here’s what I am starting with: a relatively complete 4 cylinder harness and dash.

What I need: six cylinder non EFI and with a Weber carb setup, stock distributor, no ac, wiring for this tub.

Question: if I want to use the existing gauges, steering column, heater and lighting - is it easier/better to rewire from scratch or to use the four cylinder setup as a starting point? I’d probably need some 4 cylinder senders?

Yup, got more parts from the pile today and there’s a few wiring harnesses. Now to figure out which was which…I’ve got two ecms to figure out. One setup was out of a parts Islander. Were they all 6 or 4 cylinder or was it just an appearance package?