I remember someone around here building something like that around here almost 50 years ago. He used a 3/4 ton frame with a 302 and a Clark 5th over and the 4.56 3/4 ton rear. He chose the 3/4 ton chassis because it more closely resembled the 350 GMC cab over chassis. I helped him find parts because I practically lived in salvage yards in those days, but I didn't help in the building. It didn't take very long, so it must not have been to complicated.