The 216 reaches its peak torque at approx 1100 rpm. From 800 to about 1600 the torque curve is fairly flat, then it starts to drop off at higher speeds. So between 800 and 1600 is the "torque band" for that engine. See performance curves for 1940 here:
http://chevy.oldcarmanualproject.com/chevyresto/4041.htmAn engineering analysis of your question is fairly complex... But the Chevrolet engineers considered those types of situations when they designed the trucks. Things like Rimpull, etc. Somewhere on the net, maybe Brad Allen has it, is a Truck Salesman's filmstrip guide to "sizing" trucks for the customers' needs. Other than that you'll have to learn from others' experiences.
