I had a 76 with the extended cab lwb and 4wd.
440 auto sob got 4mpg.
It would pull anything any time in any weather.
Traded it off for a almost new 94 Dakota, the payment on the Dakota was cheaper than filling up the power wagon twice a month.
100 gallons of gas each fill up is hard on the wallet even back then. The guy I bought it off of showed horses and had custom tanks built for the truck.