Dr Dave, as you can see the recommended gear ratios are all over the place. Why don't you decide for yourself? You can make the RPM calculator work for you like this:

1. Pick a rear end gear ratio to calculate on, say 4.10 for example.

2. Multiply that number by your overdrive ratio to get an "effective rear end gear ratio". In this case, 4.10 x 0.64 = 2.624

3. Use the standard RPM calculator to see what your rpm's would be with your tire diameter.

FYI - You can do the same sort of thing to get a feel for what your "shift point" would be in each gear at a reasonable rpm too. For example, with the same 4.10 gears and a 2.87 1st trans. gear you'd calculate like this:

a) 4.10 x 2.87 = 11.767 "effective gear ratio in 1st gear with 4.10's"

b) using your tire size, you can calculate a mph at a given rpm, say a 3000 rpm target shift point for daily driving, and see how many mph's you'd be going before you had to shift.

c) repeat the above with your other trans. gear ratios with a "target shift rpm" (like I just used 3000rpm) for the other gears to see how fast you'd be going in the other gears too.

Hope This Helps!