jason just a quickie re your harness idea.
firstly have a real good look at the condition of your wiring before deciding on what harness to butcher, i mean adapt
you might just save a lot of headaches down the track by installing an aftermarket harness. i used a airride technologies harness wich has several spare fuses and wires to be incorporated into the efi setup.
and with mine ( 186 with 12 port black head, vk intake manifold, vn TB, delco 808 ecu ) i found the easiest way was to use the JE camira engine harness and wire in another 2 injectors. then all you really needed was power and a couple of other little touches which escape me at the moment.
one thing to bear in mind with EFI is the need to plumb return lines to tank.
plus all sensors- MAP, O2, MAT, water, etc: the camira harness has all these already hooked up i found a hell of a lot of useless wires in the VN harness.
good luck with it.
and Ed i definately the guy with the EFI knowhow
dean