My '70 K5 Blazer is the reason I've never bought another Chevrolet. Cold with that uninsulated fiberglass top, top heavy, rusted badly and drank gas like it had a hole in the tank.
Bad years for any American vehicle. They all seemed to come pre-rusted. Quality in general was at a low point.
EPA had totally f'd things up.
Probably a gutless 350, automatic, with full time four wheel. There were a lot of those and pickups like th st around here.
Ford it seemed, did a bit better (not much) but most of those trucks were lock out hubs and 4-speeds.
With the gutless engines of that time, it helped.
Dad would only buy 4 speed, lock out hub vehicles.
A cousin had a 400, auto, with full time.
A bobtail semi does much better on fuel.