5-speed swap?

[mrtleavitt]

My truck has 31 inch tires and 3.0 gears. At 75 mph my rpm is 2600. V8 engines want to be between 2200-2800 rpm for highway cruizing. Too low is lagging the engine and too much is excesive wear. I use 3rd gear for cruising around town, the cruising speed range I use 3rd is from 25 mph to 50 mph. When I'm on the gas hard my 3rd gear starts about 50 mph and I shift to 4th about 90 mph @ 5300 rpm. Any speed below 45 mph is lagging in 4th. Like I said I love this setup! It was not expensive at all (like a 5 speed swap would be) plus I can now use all 4 gears intead of 3 and I gained a little top end gearing which any old ford could use. If you go for the T19 swap I'd reccomend 2.75 diff gears if you are going to keep those smaller tires. Smaller tires + 2.75 should be about equal to my 3.0 + 31" tires.

Here's a pic so you can see what 265/70/R16 which are just about identical to 31x10.5x15