I have a '63 C30 Dually. 250 straight six, SM420, Dana 70HD with 4.10s out back, 235/85R16 tires (31.7" tall). With a steel flatbed I average about 12mpg. When I first got it on the road with the bare frame rails I got about 15.


1963 Chevy C30 - 292 I6 +.040" 10.78:1, SM465
1978 GMC K2500



"Four gears with a granny low and six cylinders straight in a row."