i have an XLT 5.4 4x4....my buddy has an 08 FX4....do we have the same rear end gear? cause it seems like his truck gets up and goes better than mine and his is all stock vs. mine has a CAI and exhaust

 

I don't know what your gears are, but he probably has a 3.73 LS.

You can get a window sticker at:

http://services.forddirect.fordvehicles.com/inventory/WindowSticker.pdf?vin="YOUR VIN HERE WITHOUT THE QUOTATION MARKS"

Your ambient air intake is adding little (if anything) hp (maybe 5-7). Your exhaust may actually be hurting your low end torque.

 

ive been looking more and i think i might have 3.55's...can someone verify that?

 

i think that it has a listing in the f150 manual, (i think). might want to look there.

 

I think the coding of the VIN will tell you and I know my window sticker lists the gear my truck came with so you might want to check that also.

 

Sure thing.

Drive your truck over to my house (bring beer) and jack it up in the air. After it's in the air, break out the beer and write the VIN down.

Then we'll go inside fire up the computer and search the internet for a Ford VIN GUIDE. Then we'll look at the window sticker and see what we can figure out.

Once we're done, we'll double-check the tag on the rear differential.

Then we'll put the 12-18 beer cans in the recycle container, lower your truck back to the ground, and you can be on your way...

 

Look at the axle code listed on the sticker on your driver door jamb. His is likely axle code B6 (3.73 LS). Yours may be H9 (3.55 LS).
http://www.fordf150.net/howto/decode.php

 

lol ya there should be a sticker on the differential thatll tell you, you probably can just look from behind the truck without jacking it up

 

SSSHHHHHHHHHHHHHHH!

You're ruining my plan to get free beer out of this!

 

Good point. camohr - these lookups should only be done under supervision of a trained professional.