gas mileage

[carolinajohndeere]

Hi: I just bought a 1972 C50 with a grain dump bed. The brake lines were shot along with some wheel cylinders. Just got all that fixed and started driving the truck. It has a 350 engine, a 4 spped trans., and a 2 speed rear end. The rear end is a 6.50 ratio in hi range.

Anyhow, the truck runs great. The only problem is that it is getting reall bad mileage, less the 5 mpg. I know this is a low geared rear end, but a 6.50 was in a lot of the Chevy trucks.

What has been you experience with gas mileage on one of these. Once I know what I should be getting, I will start digging into the fuel system if needed.
Thanks in advance for your help.