I remember reading that the original 289 CSX cars started out with 3.54 rear ends, and Shelby decided the final ratio was a little high..as apparently most customers would have traded some of the 150 or so top end for more 'step' out of the hole. They went to 3.73 or so.
I figured that would work for me with the Tremec M-7003 R58H. It has a 2.87 1st, and a 0.68 5th. With a 26" tall tire, I'd have the best of both worlds. So far, so good