Havyek

Honestly, I'd recommend 4.56s for anyone who is at 33s and debating a gear swap.

My only experience is with Jeeps, but I've never heard of anyone replacing tires with smaller ones when it's time to replace.
ESPECIALLY with the 5.0s, they make their power/torque at higher RPMs. Idling down the highway over the 1500 RPMs you're probably at now IS GOING to affect MPG. But Smiles Per Gallon? . . . . .

rts9364

MPG could actually improve. If rpms are too low with big tires the truck will want to downshift at every little incline, which murders mpg's (and the trans, long term).

WarSurfer

4.56 is on the high end for 33s. I wouldn’t recommend that low of a gear for a daily driver.

I have 37s with 4.88s. Running 33s with 4.56s would be like running 5.13s with my 37s - I’m already over geared with 4.88s.

Browe4140

I’ve got 33”s heavy tires. With the 4.10s at 65mph it’s 1900 rpm. Love the fact that on hills that it uses to down shift to 4th or 3rd. Now it may down shift to 5th. Love it. With the 3.31 gears it would run 120 mph in 3rd. Now it shifts into 4th at 93

Browe4140

I went with the 4.10s because of pulling my 8000lb camper. And because I go to the track sometimes with it.