I know its been asked a million times. But I can't decide which ratio I want to run. I have a 03 1500 with the 5.7, I put a 3" lift and run 285/70R17. The tag on my diff says I'm running 3:91 gears. And I've programmed it and have the rev limiter all the way up. Right now at 65mph I'm at 1850rpm, and at 70mph I'm at 2k. I want more low end, I need some more *****. Will I even get much of a difference with the 4:10's? Or will the 4:56's make my rpm's to high on the highway and kill my millage?

 

I don't think that 4.10 would be enough difference from stock to be worth the expense. All the results from people with 4.56s show you'd go up maybe 300-400 rpm at 70 which wouldn't be much of anything in the mpg.

I'm always after more acceleration but I'm not disappointed with my current performance. I had a little "fun" with a new turbo Volvo the other day from 0-70 and it was pretty much dead even. Looking up the car in a magazine shows it goes 0-60 in 6.8 so my bigass truck isn't doing too bad.

 

You will see very little difference going with 4:10 gears. If you are going to go through the expense of regearing I would go with 4:56's. The increase in rpm's at 70 won't be that much like stated above 300 to 400 rpm's. But the low end torque will be a lot nicer.

 

No way going from 3.92s to 4.10s justifies the cost of the swap, get you some 4.56s...

 

^^^^^^^^^^^^^^^^
What they said. A .18:1 shortening won't even be noticeable.

 

Awesome thanks guys. I'm gonna do the 4:56's later this week. I'll let you know the results