Hi rog
I'm about 3/4 the way thru wiring my Harrison. I picked up a Painless 18 circuit loom on Ebay for $250.00 and with the occasional phone call to a auto sparky for advice, it's been pretty easy and good fun. I suggest having a mentor if you've not done it before as there's bound to be a few traps awaiting you. For example my Mitsubishi combination switch switches lighting to earth which had me buggered until the elec redrew the painless diagram for me. There's quite a bit on the universal loom instructions that need to be modified to suit your needs.
You only need about a dozen circuits and the painless only had 1 relay for the horn, so you need to add a few more. The Yanks don't have a separate circuit for reverse lights and integrate tail/indicator lights as well other idiosyncrasies.
You'll also need to integrate the engine loom where some operations are replicated. My car is running an EFI Windsor and I gave the engine loom to Warwick to modify, he stripped out the unnecessary stuff and just left me with a few power/ignition connections to wire in.
Get hold of Graeme at
www.larpro.com.au for wholesale supplies. I used heaps of 2,4,6, & 8 pin plugs, they're about $6.00 each at Supercheap Auto, try 40c from Graeme!! and his wire 30m wire spools are the same price as 7m from retailers.......got his contact from this site, he'll save you heaps.
At anywhere from a few to the 6 grand that someone on this site was charged to do the job, it's worth persevering if you're 1/2 confident.
Greg