I had a 69 3/4 T 4x4 GMC for years. Man, I loved that truck. It would go absolutely anywhere.
The only thing I would suggest, if yours is 4x4, replace the front diff with a '70s diff. the full-floating '69 is awesome for bearing life, but the ball-and-socket is a bugger to keep seals in, and the '70s diff will give you disk brakes in front... well worth the switch...
And headers/dual exhaust (2 1/2" pipe) for power and gas mileage as with all Chevy small blocks... :D
The ‘69 is a 350, 4 bbl, 4 speed, 2wd, split rims.