[earl84]

I am installing an American Autowire harness in my 66 right now (well I am out of town RIGHT now) but I ran that wire for a third brake light up to the dome light area for now. I plan to install a third brake light off of a Suburban, like this http://www.persh.org/Pickup/ThirdBrakeLight.htm

Here's the info on the third brake light:
P/N 15755976 Third Brake Lamp

GM 94-09
Escalade, S-Series, Blazer, Jimmy, Bravada, Suburban, Tahoe, Yukon, Yukon XL, Hummer