I pull a 16-foot flatbed trailer with my 66 C-10 and get about 8 mpg. It has the original 250, 3-speed tranny and a 3.73 posi. I notice the trailer empty in all 3 gears and especially going uphill. Empty it gets between 11 and 13 mpg. My grandpaw pulls the same trailer with his 71 C-10 with the same drive train, but he has the truck loaded to the max and has a John Deere 750 with some kind of emplement and we have to us second to get up most hill in my area. Mileagewise, he never checked it. But stopping is a different story since his has the original brake system, mine has a rebuilt original style hydraulic system and neither of us have trailer brake controlers. My dad drove a rig for a local grocery store chain and he said that there is a big difference when the number of tires on the road is increased.
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66 Chevy C-10 restoration project/work truck
