[A/S] tow speed

["zigzagguzzi" <jvasil@xxxxxxx>]

I have an E150 ford van with the 5.4 v8. I just changed the rear gears 
from the 3.55 standard to the 4.10 set. I am used to traveling no 
faster than 65mph and am interested in what rpm I will be turning at 
that speed or slower with this new gearsetup. I have no tachometer so 
mph would be a good reference point. Also, should I use the overdrive 
option now that the gearing is changed ,will this affect the torque 
converters ability to lockup? I tow a 22' CCD,  thanks jim