I'm trying to figure out what gear ratio to run. I've got a 700r4 and going to run 39.5's. I used the calculator, and figured a stock z71 at 3.73 and 31in tires. This was almost identical to me running 4.88's with the 39.5's. This is going to be in a nissan truggy running a 350, and driven on the road also. So should I run 4.88 or 5.13?