Hey Al.....there are two harness kits I would recommend.
The painless of course. 12 or 18 circuit. use GM color codes.
http://www.painlessperformance.com/catalogframe.htm
or Ron Francis...18 circuit and either GM or ford color codes.
http://www.parts123.com/PartFrame.as...FRANCIS_WIRING
Either are excellent kits.I used the painless because the fuse box was smaller and I didn't want 18 circuits. Sadly I should have used the Ron Francis one as he has a ford color code harness.
I got my painlessfrom some performance shop in Sydney....cant find the invoice to advise you but should not be hard to find. They have full page ads in the V8 performance mags.
Let me also say this.....A couple of mates have had professional wiring....behind the dash was neat but a bluddy mess when you got in and had a look. All terminals were crimpted and some were poorly done. One had intermittant problems and the fault was bluddy difficult to find.
As mentioned, I used Painless.....the color codes are easy to follow...the wires are prefitted to the fuse box....and just run out to the ends....all you do is run them to where ya want....terminate them....hook them up...prove the system works....then run them as neatly as you want...then cut and reterminate....I also crimped and soldered all terminals and used shrink tube.
The Ron Francis kit works the other way...he starts at the other end and works towars the fuse box....every wire in the kit has a matching terminal at the fuse box......how easy is that?
Dont cut any wires until you have them routed where ya want em.
Certainly, I had some gauge wiring to do behind the dash but anyone can wire instruments. Painless provides all the fused and hot feeds to the dash.
Simple...really easy....and.....By doing it yaself....you will know it backwards...any problems and you know where to look. They certainly remove the mystery of wiring a car.