your running 4.56s and a 6L80e?
Thats the same setup im planning on running.

 

I added a Airaid jr right before I swapped gears. Truck did gain 1mpg city driving, not sure if the added mpg was due to the intake/gears or both. Have not had a chance to make a long trip to see if it helps any.

Yup, def helps the truck get moving.

 

I need to stop clicking on these threads. I had all but made up my mind that if I was going to do any more performance mods, I would just throw a supercharger on it. If regearing a 14-bolt 4x4 truck didn't cost so damn much, it would be done already

 

ok lets see i have the big boy 8.1l that has 305/70/16's and going from a 3.73 - 4.56 was the best mod i did.. lost a wopping 1mpg but going from 13-12 didnt matter much. towing my 16k camper i went up from 6-8 mpg. now the motor is fully built and whipple charged and the last trip i had (100 miles round trip) i still had 12 mpg. hope this helps make your mind up on the 4.56

 

i'd say 4.88s but if you plan on going 6 speed do the 4.56s save some $$$. i'm running 5.13s on 37s runs about 2200 @ 65

 

the more and more i think about it i want 4.88s but they would be killer rpms with my 34.5/11.5s

 

You have the 4L60E dont you? i dont see what year your truck is.

Roughly 2350 for 4.88s, 34.5" tires in 4th (60E)

With the weight of them tires and the non aerodynamics, you would prolly be better off turning more RPMs so it wont be bogging all the time.

 

Yeah i have the 60e. My truck is a 2008 with the 5.3, do you think i would dip below 11 mpgs with 4.88s and 34.5s?

 

I doubt it.. it should help it more than it hurts it.. that poor 5.3 is staying in PE now trying to cruise im sure.

 

PE?? Im not really to worried about mpgs i live in Louisian and gas is like 3.60 a gallon here and has never gone up over 4.00 a gallon. Knock on wood. But i dont wanna burn 4 gallons of gas going to work.