I put a Saginaw overdrive unit in a '54 'bolt, moved the 2000 RPM cruise from 55 to 75. The problem is the brakes just don't have a lot of stopping power, so be careful if you do that. The transmission with o.d was exactly the same length as the 3 speed so drive shaft fit perfect, shift linkage and all. I happened to have a few o.d's around so it was a no cost item for me, but I think a 3 sp. w/o.d. is available in older wrecking yards for $50 to $100. I really think this is the most practical solution to raising the freeway cruise speed, and lowers the noise from the drive train too.
