Revving too high

[my67c20]

So here is some numbers to consider. For every inch in diameter your tire grows you gain 2 mph at a given rpm. For every inch your tire grows you reduce your rpm by 100 at a given speed. An overdrive transmission will reduce your rpm by 600. Changing rear gears to 3.42 drops rpm by 250, and 3.08 by another 250. Assuming these are available for your axle. Estimate gears to cost 1k per axle, or tires 1k per vehicle, or transmission 2k per vehicle, best bet is to go the tire route. Might be a dog off the line, but you have the granny gear, but you gain on the high side. Also with the gear ratio of the SM465, this may give you more range in 2 and 3rd. So @ 2500 rpm the max speed in 1st is 9, 2nd is 16, 3rd is 35, and 1st is 55. With 6" (34") taller tires @ 2500 rpm the max speed in 1st is 11, 2nd is 19, 3rd is 43, and 1st is 67. Just my 2 cents