What is maximum gear ratio?

What is the best gear ratio for a F350 4x4 with 7.5L gas engine?

• I have a 1997 F350 4x4 off road standard cab truck with the ZF 5-Speed manual, 32" tires, and 3.55 ratio gears- bought the truck about 2 months ago and it has under 20,000 original miles. It cruises at 2000rpm+/- at 70mph in overdrive, and seems to haul my 20" center console boat fine, but doesn't blow any doors off. I think the 3.55 ratio never had a place in a 1-ton truck, and I want to put a lower gear in it for better towing performance without bringing the 460 out of it's low-mid rpm range. Other than a performance exhaust, it has no other modifications but will see a full Banks kit in the future and a max tire size of 285 75r 15 (33"). The 4.10 ratio may be the best compromise around 2300-2400 cruising, but would a 4.30 at 2550rpm at 70 in overdrive be too much? The truck is not a daily driver and I want to take as good of care of it as possible. I envision having a 25-30foot boat within a year or so, and would like it to be better equipped for such a load.

• Answer:

  How much does your boat weigh? With an overdrive transmission, I'd say that 4.10s are the way to go. If you're going up to 33 inch tires, 4.30's would put you at about the same RPMs as 32's with 4.10s. So that's something to keep in mind. The 460 has enough torque to do either really.