This summer I plan to have my dealership install a factory LS in my 3.55 non-ls FX2 (I'm having them do it so it will be covered under my warranty). I have the factory 20's with the pirelli tires. While I'm having the LS installed, I may have them change out the gears too. For the next 1.5 years, I will be in college and my driving will be about 70% city and 30 % highway. However, once I graduate that will change to about 20% city and 80% highway. I was planning on having 4.10 gears installed, but I don't know if I should now. Would there be any point on moving up to 3.73? Your guys thoughts?

 

I don't think you'd notice much, if anything going to 3.73s. 4.10s seem to be a good compliment to factory sized tires. My boss has a chebby with 4.10s and about 28" tires with the 6.0L. He gets about 12mpg city hoppin - and it's a 4 door long bed with HD suspension package.

I don't think you'd see a big hit if you can keep your foot out of it in the city.

 

I'll admit my right foot is a little heavy... but I'm only 7 days away from 21 so thats to be expected. My truck is a 2007 FX2 Supercab w/ the 5.4.... so your sayin the 4.10 wont kill my mpg? I'm averaging 12-14 mpg right now combined.

EDIT: I think the stock tires are like 32 inch tall? I think thats kinda dumb why the FX2 on 20's would come with such large tires...

 

The gear change will run around 500.00 Even if you gain 2mpg it will take you many years to pay off that 500 with your improved mileage

 

yeah I know im not doing it for MPG... I want to add an LS and want 4.10 gears, but I am worried about the gears killing my already pitiful avg mpg