Im gonna add 4.11 youkon gears, bored throttle body, comp cams and valves, k&i cai, flowmaster 40 series. Im gonna need some more power because im gonna add a 2 inch bodylift and 31 all terrain tires. would all this stuff give me enough power not to loose alot of mpg with the 31s?

 

The gears, lift, and tires arent going to help much with gaining MPGs.
I would think you might even out.

 

im not gonna put the gears on it anymore but how much mpg would i loose if im at 17 stock right now?

 

well the bigger tires, the lift would take it down a few. the CAI may take it up one or two along with the exhaust, add in a highflow cat too.

 

I might get one because my truck looks like someone drove it under water as much rust as it has under it. Will it sound better with a highflow cat on it?

 

my old blazer was getting 17 mpg with oem size tires(27"ish). i went to 30" and lost 2 mpg.

with 31's,you might be ok. Actually,what gears do you have right now? If you look in the glove box,youll see a big sticker with 3 letter/digit codes. find the gu codes. it'll be like gu1,gu2,gu3,etc. list it and i can find what you have if you dont know.

 

i have 3.42 gears right now but when i get the 31s im gonna put 3.73 in it

 

Cai wont increase mpg bigger tires definately will make your milage worse as will a lifted vehicle. Making more power will result in more fuel used.

 

I know that I'm just gonna put bigger tires to make it look better

 

OPEC loves you.....and your 31s