My 33 Chevy has 3.08 gears, 700R4 (.70:1 overdrive) and 29.5" tall tires...gives me 1596 RPM at 65MPH
Now the truck I'm building has a 5.13 rear gear ratio, NV4500 5sp with .73.1 final overdrive and 32" tall tires
that figures out as 2556 RPM at 65MPH...a bit more fuel consumption.