i have a 97 f150 5.4 w/e4od tranny w/ 3.55. my tire size is 245/70/16 and was wondering of 3.73 would be good for me. i do mostly highway driving about 70%, i dont want anything that would hurt mpg just enough to get off the line a lil better. i get 14 mpg if i baby it just feels like it needs a lil more. i've been reading treads and a lot have done 4.10s but i feel its too much. so tell me what u think would be good. thanks

 

Don't waste your money. You won't even notice the difference.

 

With the 3.55, it's not worth the money switching to 3.73's. Go with the 4.10s or don't change at all.

 

i only have a 28 in tall tire so u wont think the rpm's wont be to high doin say 75

 

you only need to change if going up significantly in tire size. just do horsepower mods unless u go 2 a 35 inch tire

 

your rpms will only jump 500 roughly

 

that's quite wrong, you don't need to do anything, but 4.10s will greatly out do just about any bolt-on performance mod you can do. In fact; after a custom tune gears would be the next mod if I bought a new truck tomorrow. But I'm running 4.30s on a 29" tall tire, so what do I know.

 

i hope your not advising people to run 35" tires with stock gears... cant figure out if your advising a gear change or not lol

 

you misunderstood; I was just saying he doesn't need to change with 28" tall tires, but he asked about 4.10s so I'm assuming he wants a lot better get up and go off the line. And to say that I have 4.30s with 275/45/20's 29.74". GIP1979 is the one saying not to re-gear

 

Do you have a 4x4? I just did a gear swap from 3.55 to 4.10... Still in the break in period did a mpg check and it went to almost 16mpg It went up about 2mpg. I would have went to 4.30 but I was unable to find that gear for the front in a 4x4. I am also running a 265/75/16
everybody is correct when they tell ya to make the jump to 4.10 you will be throwing away a lot of money if you make a jump(baby step)lol to the 3.73
I went with motive and a gr8t mechanic I'm very happy with my swap.

 

scouty how much did your gear change run you start to finish? I am wanting to go to 35's in the next year or so and before I do that I want to regear as I tow alot and dont want to lose that much power from the 33's i have right now..i have the factory 3.55LS on my 5.4L 4x4 supercrew

 

I believe it was around $1300. That was for 4.10 front and back, Auburn HP rearend, 2 mini install kits. (I only had 52,000 mi. on the truck) fluid, and labor. I went with motive gears. My mechanic said that everything looked great, and there was no need for the master install kit. My mechanic has been doing this for 15yrs. he set them up great they are very quiet.
I am running a 265/75/16.
I finally was able to get into the gas a little and WOW. and I am also getting 15mpg up from 13. 99 f150 5.4L

 

so im thinking maybe i need to go to 4.56s? im wanting to run 35s

 

That sounds about right... I did alot of research b4 I did my swap. and alot of guys said to go to the 4.56's if I plan on going to a 35" tire i'm staying with the tire I have now. I just wanted to pull better, the truck is still a daily driver unless its nice out then the bike comes out.