I want to do a gear swap in my 4x4 5.4l 03 scab. I have a xcal 3, duals, cold air intake but i dont think the 3.55's are cuttin it. I dont want to kill my mph. Any suggestions????

 

What size tire are you running? Are you lifted? Are you going to get a bigger tire?

The top end will suffer a little with bigger gears but your drive train will work more efficiently.

Here is a really good link, first page shows how they are done, second contains a lot of useful info on gears.
https://www.f150online.com/forums/ot...p-rev-1-a.html

 

The 4.10's will help your truck out alot. IF it has stock tire size or under 35's

The 4.10's and stock tires will hurt you mpg when on the highway (65+ mph) But all in all you could possibly see an overall of 2-5 mpg increase.

If you do plan on going to a larger tire (35's) then you might want to look at 4.56's or possibly 4.88's if you plan on going 37's or bigger

 

right now i am going to keep the tires stock. I am running 285/60 r18 on my tire. the 3.55's seem week. i appriciate the input guys. i will look for some 4.10's!

 

4.10's will work nicely for you. id give them a try

remeber the rear axle is a 9.75 and the front is an 8.8R (reverse cut gears are needed)