Ok I have the 5.4 liter with a roush supercharger on it. I plan on changing the pulley, installing colder plugs and getting a custom tune. With all the added horsepower i want to change my gears. I currently have 3.55's i want to put in 4.10's or 4.30's. Does anyone have any suggetions on what to install i do want to be able to cruise the highway.

 

What size tires do you have?

 

They are 305/45/22

 

im about to get gears installed to been doing alot of research into gearing since i do alot of higway drivin too
i would go 4.56 if i were you
any idea where your gettin the install done?

 

I might take it to JDM. Im probably going with Yukon 4.11's. With 4.56 wouldnt it be revving really high???

 

2wd or 4wd. if 2wd i would get some 4.30's but if a 4wd i would say 4.10

 

Those tires are 33's. Here are the RPM's at 70 mph in OD, converter locked:

3.55: 1800
4.10: 2050
4.30: 2150
4.56: 2275

 

Sorry they are actually 305/40/22 and i measured them from the ground to the top of the tire and it measure 31"

 

oh in that case i would definitely go with 4.10's

 

Those are 31.6. Add about 100 rpm to my numbers.