Steve
I have the same truck and drive train as you do, only a "67" model. Mine looks to be a longer wheel base though.
GMC 9500 series,637 gasser with 5 speed and duel spotlights like yours.
It was an in-service Fire truck when I bought it about a year ago.
Hope to get it to the Stovebolt Reunion in KC this year. Have some throttle linkage and vibration issues to correct before I would try making it to Kansas City. Sure would hate to pay the tow bill to get it back home.
Guess I need to take time and send Peggy some pics to post in the Gallery.
Check out the photobucket link for a few pics.

Don


1967 GMC 9500 Fire Ladder Truck
"The Flag Pole"
In the Stovebolt Gallery
1946 2-Ton grain truck
1946 3/4-ton pickup,
1953 1-ton pickup
1957 1-ton flatbed dually,
1954 Pontiac Straight Eight
Of all the things I've lost in my life, I miss my mind the most!