Hey guys, I've searched and didn't find much.

I want to do the 6.0 swap, but i want to know how much this will hurt my mpg. I get about 13 city and 15 highway if i baby it. Idk if i can handle much worst, it is my DD. Don't get me wrong i'm not looking for 30mpg, i bought a truck to drive a truck.

Thanks guys, any help is great!

 

Here's the bottom line. All LSx engines are very fuel efficient when cruising on the highway. But they are pitiful when it comes to stop and go.

I swapped to an LQ9 from a 4.8L. City mileage is roughly the same, maybe down a little bit. I've averaged about 13.5. The 4.8 got 14, but one tank I did get 10. And I don't go around mashing it either. On the highway though the 6.0 is excellent. It gets actually better mileage than the 4.8 due to the fact that it never shifts out of overdrive. I get over 23 mpg on the highway with it (3.42 rear)

 

Well that's not near as bad as i thought.

I've just hear stories about guys with 1500HDs getting 13mpg highway.

 

Last time I checked a 1500HD is a lot heavier, has a much beefier rear end, and has a 4L80e tranny. That's the cause of the bad mileage, not the engine.

 

x2 on both things GMC said.
My 5.3, with mods in sig gets better mpg than my grandpa's 07 4.3 v6. In all honesty if you can find the right size cam without going over board, you can even get better mileage than stock, assuming of course you get it properly tuned.
I say throw the 6.0 in and don't look back. I'm getting 16mpg avg right now with my 5.3. Mainly because i'm waiting on a wideband so i can work on my tune. plenty of people with 6.0's are doing better.

If i drive it like i stole it i avg 14-15

 

Will all bolt on parts i buy for my 5.3 swap to a 6.0?

 

every single thing swaps over

 

That's great! This is something i want to do,but will probly have to wait till next summer, unless the 5.3 lets go before then. I'm planning on headers and E-fans soon, after i get it tuned.

 

Nice, the swap is easy so far as the fact that it's the exact same thing dimensions wise. But it's still a lot of work and a pain. It took 2 experienced car ls1 guys (not with gm truck engine swaps though) 18 hours to swap mine out. We did run into several problems along the way related to my swap engine though (3 exhaust bolts broke off).

 

3! WOW!

That's pretty much the same kinda guys helping me. They loved there cars till i took them though a creek and up a near vertical hill. lol