Davey, The factory shop manual for the 67 will have the wiring diagrams. When ever I get a new project I always find a factory manual for it. I may also have also have the wiring harnesses for a 69 GMC, I'm not saying they are the same. The wiring diagrams are also on the web, I've seen the address in quite a few posts, never book marked it for because I have the manual. I also have the crimp 0n spade connectors.
Larry

I don't own a vehicle that isn't old enough to drink.