I just bought a set of 35in tires and the truck is a bit sluggish to say the least. I was thinking of changing gears, but i can't decide between 4.30's or 456. My driving is mixed between highway and city. The 4.30 gears are made by motive gear, and are listed for the ford 9.75. I'm leaning more towards the 4.30 gears, but i would like some opinions, as i only plan on doing this once.

 

I'd go with the 4.56s without a doubt.