Huh, I never knew that. So with the 700r4 I believe the super tall OD is 30%, 25%? With this equation, at 80mph in D at 1:1 that puts me at 3714 RPM if I go with the 4.56s. In OD that drops me down to 2600 RPM if it's 30% (which is actually pretty good) and 2786 if it's 25% (which really isn't even that bad either considering I'm going 80mph in a big ass truck). Works for me. Obviously I will drop my speeds if towing heavy trailers like the 3/4 ton I seem to pretend it is, but for normal daily use 4.56s actually sound perfect to be honest.