[bailey_57]

i'd definitely go with the 3.73's, and how are you doing 55 at 1400 rpm in drive, does anyone else think that sounds a bit off. i think you still have overdrive functioning. set up your problem as a proportion. the gear ratio and the engine rpm are directly proportional (in other words as one number increases so does the other). Now given your scenario where you are turning 1400 rpm with 2.73's and you want to know what rpm you'll be turning with 3.73's, and your speed of 55 mph is the constant between the two events you would put 1400/2.73 = rpm/3.73. Your unknown is the engine rpm, so its a matter of cross multiply and divide. Multiply 1400 times 3.73 and divide by 2.73. i came up with 1912.82 rpms this will work for any gear ratio you plug in. I wish I could've used stacked fractions it would look alot nicer.

Hope this helped.