I'm about to swap from 3.42 to 4.10. My truck is a 2wd 5.3 with 20's. My question is will there be a big noticeable difference and will a tune be a must immediately after. Will it be driveable after the gears with no tune?

 

you can drive it just take it easy till you get it tuned. ls motors like 4.10s and so will you.

 

big noticeable difference, same swap for me
and you can drive without the tune, but you'll have lights on, and it may or may not affect your traction control

 

I won't be driving it long untuned, I just wanted to make sure it wasn't gonna hurt anything.

 

just gives you another reason to "go easy" while breaking in the gears haha