I am thinking about putting a ranger overdrive in my 66 C30, not to go faster but rather to save gas and be able to split the gears. My truck is used for work and I need to keep the low geared rearend but its hard to afford to drive it much at 8 mpg. I am curious how much difference an overdrive would make in fuel economy. If I could pick up at least 2 or 3 mpg it would probably be worth it
