Let me say this...it's not something that I make a habit of...but it's not unusual to run past the "Century" mark running across the state on occasion. That's why we run "W" rated tires and don't leave home without "Beltronics"...right Red? LOL

Blackbear is awesome. Make sure you tell them what mods you are making or have made. This impacted the tune greatly. The other cool thing with Blackbear is is you make a mod after he will re-tune it for free. Just have to rent the data logger to supply info.

^^^^this! Black Bear Tuning, Tuning By Zippy, PCMForless, tuning by Krambo. And HPtuners will be your friend. Lol. Those are just a few but a actual tuned computer is best over chip. The other more important mods would also be trans. A 40k lb trans cooler and a shift kit (which is adjusted in tune) will prolong trans life and give overall better performance. Just a few ideas. Could also change to a lower temp stat so the computer will add more timing making for more power. I was all over the LS1tech, silveradoss, camaro5, gmtrucks, fullsize forums, tbssowners and a few other forums I am also on. 6.0's have great power potential. And there biggest like is the 8.1 marine injectors that I'm sure many here have. Lol

How do you like you 2500 Avalanche? I really like the '03-'06 2500 Avalanche with the 8.1.

I love my Av 2500. Power, comfortrable and no diesel smell................

Had one, and loved it. I've posted a bunch about it on here. Search "Avalanche 2500".

I sold it with 50,000 miles or so. Transmission had valve body and TC replaced when nearly new, but trouble free after that. Last time I saw it it was approaching 100K miles and looked great. Get the 4.10 rear end, and a few other mods I've mentioned on here in the past.

Just adjust the timing in the main spark high octane table and the ect spark multiplier.

I have a 03 2500 Ave and love it. 8.1 with 4.10 gears. Removed the cats, 4" MBRP diesel exhaust pipe with 4" flowmaster, K&N filter, tuned on friend's chassis dyno with HP tuners. Got 60 rwhp gains. Sounds like a big block should and gained 3 mpg over stock, corrected stock lean conditions and it quit using oil. I have a 496 Mag HO cam and an LS2 ported TB on the shelf for it along with 4" lift waiting to go on. Just need to find a set of reasonably priced marine injectors Headers go on next week while it is being repainted. 140k miles and still strong. Roughly 370 HP at crank now and runs well for a 7400 lbs truck and rides like a caddy that can move mountains. Looking for 425-450 hp when cam change is done.

Dont waste your time...buck up and buy a Duramax. My 06 6.0 got 10 miles to the gallon. They are prone to piston slap. It turned 100K and lost and oil pump. My cousin had an 05 that lost the oil pick-up tube and ruined his motor. I wouldnt want to pull my boat to the lake with a 6.0 unless I lived in Kansas.

Thanks
I've searched your posts and they are very informative.
I have a friend that had a 2500HD 8.1 Silverado and I am quoted on this site stating that it was the worse gas mileage vehicle I had ever been in. Now I am ready to eat my words and am looking for the Avalanche with the 8.1. I was going to go with a diesel but with the lack of miles I drive and the maintenance the MPG just does not favor it. My truck now sits all the time since I picked up my Cadillac, and I will keep my 1500 for a shop truck or anything I don't need the 2500 for.

Now back to the regularly scheduled topic of this thread :)