I was editing as you posted...no worries, not pertinent info, just that IDGAF about mileage as long as it has some steel around it and doesn't drive like a turd-cicle. My dad had a 85? C10 back in the day. 305 turned 350 when we had to put a new (used) engine in it, very likely had 3.08s because it would just idle along at highway speeds. I recall it getting really decent mileage (carb engine), I was only 16, but compared to his old truck 74 Camper Special 454, my 455 76 Buick, moms 500 Caddy and my 400 70 Impala, it felt like 30 mpg. I could go all the way to northern WI on one tank of gas everything else took almost 2 tanks, except the 74 pickup. It would drain both saddle tanks and have to fill up before you got to the cabin!