Rear end gears / programer...help

[04YUKON]

So my adventure has begun...
My 04, 4.8l on 24's is guzzling the fuel and struggling when towing the 4000lbs boat...

From fl to mi i was able to run about 65-75 but only in 3rd gear and about 3k on the rpm when it switched up it lost power and speed and dropped back to 3rd i was able to get about 2-250 miles per tank.

I have upgraded to hi flow cats and magnaflo exhaust but need a lil more.

Im not lookin for "tractor pull" as i dont haul the boat all that much... But i am headed for seattle in a cpl weeks,,,
i want more power but want to be able to reach the 100mph range if need be and not be turning 7k rpm

im looking into changing out the rear end gears...
1-will this help
2-4.30 0r 4.56?, and for those of you with thease gears. What kinda rpm and mileage are you getting when running at 70+ mph
3-rough cost for this kinda job?

Programmers= as it seems...bb is the shit!! But is it what im looking for or do i need something else..?
Suggestions...?

I want the haul ass but need the power too. Also considering an sts turbo kit... Suggestion on that....

Thanks...

 

[JKmotorsports]

I'm running 4.56 gears and 24s with 305/35/24. That tire has an o.d. of about 32.5", and with 4.56, I'm turning about 21-2150 rpm @ 65 mph. As for fuel economy, it went up about 50 miles per tank since the swap from my stock 3.73, but not sure how it will compare to your setup. The cam in mine likes the higher cruising rpm.
Gears will definitely help, especially running the smaller 4.8, 24" wheels, and towing.

 

[04YUKON]

Jeff...i appreciate the feedback,,, yer truck is insane...
What is the diff in the gears
4.56
4.30
4.10
off the line the truck is fine... Its just crusing and mountains that are a problem... I knoticed in one of yer pics that you at one point hauled a boat so you are who i am lookin for... I want to know best case senerio... All the way around...hopefully oneday i will have your kinda power and no more questions... I was told that the 4.30 will cause the truck to run around 4k at 70mph true? I guess what im saying is i dont want to be a gas station hopper... So if the 4.56 is yer suggestion.....what about the prog.? Would you go bb or adjustabe since i will be changing drivinng styles freq.

 

[ThwopKing]

Also if you want a turbo just for towing power..forget it. You would have to be in boost ALL the time while towing and there goes your mpg's and durability. I say add the gears..and whatever other mods you can afford..headers..small cam, nothing extreme, throttle body and a tune.

 

[blueflamed03]

agree, with those rim and tires, 4.56 and BB tune, hands down Scott.