I have a 5.3L with 3.73's with a 275/60/17 tire and it isnt enough im going to swap in some richmond 4.10's along with a Auburn HD posi unit. With the 3.73's and my tire size im cruzing at 2000 - 2200 at 70.... O yea the sire size im running is the same height as stock. a 275/60/17 is 30 inches tall just like the stock 255/70/16.....