81 cab 78 wiring?

[bns454]

hi ive swapped my 78 c20s cab to a rust free 81 cab I have kept the 78 steering colloum and wiring just plugged it in
both trucks were 6 cyl and theres now a small block in the bay ive got it running by hardwiring the dizzy and starter
the 81 engine bay loom has been hacked to fit lpg and its not making sence to me the old cabs 78 loom seems simpler and less hacked the engine just has a Rochester and hei dizzy will the old loom work?