Wow, my first truck was a 71 GMC that I painted almost that same color! really brings back some memories.
I miss that truck.
All mine had was an olds 307 with a th350.
I cant tell is that a 1/2 or a 3/4 ton? on the sticker in the glove box on mine my truck was ordered with leafs in the rear but most I have seen have had coils with radius arms. I dont know if the 3/4 tons are different though.