What will really help?I was thinking dioblo programmer and maybe exhaust what do you guys think?

This is my first post also.

thanks
Jeff

I did an airaid intake and magnaflow muffler on my 1500HD with the 6.0. I gained about 1 or 2 MPG. Better pickup as well.

Did it make it loud?I have never heard one with aftermarket exhaust.

Also just FYI I got 305,s on this truck with no problems.

I just did the muffler replacement and it is quiet inside and when you floor it you can hear but there is no interior resonance. I love the muffler but wish it was a little louder. You can have a nice quiet conversation inside with no problems.

I did a 4" magnaflow full catback exhaust. k&n fipk and hypertech programmer and regear to 4.56gears for my lift and 35" tires.
nice increase in power and 1to2mpg when i can stay off the gas pedal.

James

I dont' have a 6.0, but I have a 5.3 and an 8.1, and I have a muffler shop put true duals on mine with an H pipe. I have never dynoed a truck before and after the mods, but they seem like they respond to the mods pretty well. I also open up the air box by taking that piece out that attaches the box to the fender. It just pops out and doubles the air inlet size. I also take the screen out of the mass air flow sensor as well. I have done this on 5 different trucks. It gives you a bigger air inlet, and doesn't cost anything. The exhaust if the only thing I do, that costs anything, but opening up the air inlet really makes a difference. It growls real nice.
As far as mileage enhancements, I am not sure I have gained all that much there, but the truck sure sounds better.

I have used Dynomax Super Turbos on all of my trucks that I have done. I like the mellow tone they have. They don't flow as well as the straight through mufflers like, Magnaflow and Ultra Flos do, but they are not nearly as loud as those, and I am getting a little old for the real loud mufflers. :)
I know loud is very subjective, so some will say that the straight throughs are quite, but I don't like that droan that they produce with echo tubes at cruising speed. Drives me crazy.

Ive had many 6.0 company trucks put superchips programmer on them its by far the most user friendly and as far as limits and power is best. but customer service SUCKS. Diablo has a horrible time with keeping the programs in there limits was always bouncing off of limiter plus customer service really sucked. I have recently gone to the quad programmers not as much power as the superchips but is really user friendly and customer relations is great but does set a code that has to be cleared every so often. noticed the best mileage with superchips and a kn but again customer service sucks and the problem is sometimes when you take the programmer off and put it back on it needs updating and the scum bag that is in customer service says that the programmer need to be taken off the truck but you cant if the programmer says contact superchip for update. diablo was the worst as far a mileage but had good power but never could keep the same shift points or rev limiter one time it might shift at 5500 rpm and the next would stick on the 6200 limiter and not shift back out and stand on it again and stuck onlimiter customer service was none excistant and really sucked when you did get a responce 3 month later made a person that was experianced in these programmers feel like a dumb s*&% so far the quad has done me right but only have 2 programmer compaired to 6 superchips and 4 diablo sold 4 to replace with superchips.and questions email me at davis3210@hotmail.com ive had them all and would answer any question you have

Had a '03 6.0 2500hd with 4.10 gears,added a Hypertech programmer K+N filter and Gibson aluminized catback exhaust.Gained 2 mpg,much better throttle response.Downside was the Gibson,good fit and qaulity BUT windows in the house would rattle when you started it.WAY to loud not to mention a God awful drone at 40-65 mph.Drove me nuts,came close to putting the oem muffler back on but added a resonated stainless tip that did help some. Traded it six months later on Duramax couldn't be happier.

I put a Westers 91 Hot Tune on mine with a Corsa Sport cat back exhaust. I picked up 2 mpg on the highway and 1 mpg in town. The tune really made a difference in the midrange. The 6.0 is not a torquer motor with having the max torque at 5000 rpm. If you want or if you're good with a computer you could try EFI Live and do your own programming. Stay away from the Hypertech, it'll just make the trans slam into 4th and ping on hills.

The Corsa exhuast is pretty pricey, but at highway speed you don't even know it's there until you get on it. I didn't notice any more power but it makes the power I have sound so much better.

I haven't done the K&N - I've heard since they flow better, they let in more dirt. Plus I don't want to hear the honking sound every time I get on it or towing a load up a grade. I've heard that the AC / Delco filter actually flows almost as well as the K&N and grabs more dirt.

i think the best thing to do is a bolt on exhuast like magnaflow, gibson, corsa, ect. with a programmer and a nice intake. on my old 5.3l i had gibson exhuast, kn fipk intake, and a hypertech programmer, i also descreened my MAF. i kno this isnt the 6.0 but is very similar. my moms denali has the 6.0 and we put a kn drop in filter and it actually added alittle power at higher rpms, id really like to put a intake and programmer in it tho and she wat it does.

thermostat - programmer- air intake- exhaust - headers

Don't descreen your MAF!!!!!!!!! Do a search, it's been discussed a million times.