I think Dan said his AFR's consistanty dip into the 13's every time he moves the accelerator, even a little. Then the ECM takes a bit, but will correct it back to 14.5 ish. That seems very inefficient. I know my vortec 7.4 is older, but heck even that thing maintains a stable AFR.

Are you asking me?

If so, I'm happy with it. Its a 97 dually 4x4, 4.10 gears, stock but with a tune. Pulls the boat just fine, no problems going 65-70mph, with the ac cranking and the boat behind it. IDK, is it gonna outpull a new diesel? Heck no. But Im not into drag racing my tow vehicle. Wait, actually i take that back, lol, Icdedppl and i did drag race. My 97 454 dually vs his 7.3L chipped up excursion! But, I really dont use the truck for much, other than tugging the boat around.

My model doesnt have that fancy computer deal that displays unrealistic and incorrect mpg figures. I have to figure my mpg via a piece of paper and a pen. Best i ever saw empty, was 13.4 on a long trip of hwy driving. Normally, combined city/hwy, I see around 10mpg. Towing, I was getting around 8.

When I had my PCM tuned, I had them correct it for tire size. I went from stock 225/75-16 tires, to 245/75-16 tires, which i believe were around 1.5'' taller. Icdedpeepees truck had 215/85 stock. Now has 235/85 on it. I think about 1 or 1.5'' taller than stock.

I am asking you. Thanks for the response. A new diesel is not in my cards. The limited amount of pulling I do, I can't justify that cost (both fuel and maintenance). Have been considering a 2004 to 2007 8.1, but they are hard to find clean and equipped as I want. Just was not sure how a Vortec 454 truly pulled. Have though about looking for one, but unsure of towing capabilities.

Borrowed a buddy's 2003 Ford F250 7.3 PowerChoke last year. Only has 60k miles and was truly a gutless turd. 7-8 mpg towing and at times floored and struggling to get over 45mph through KC interstate and on some of the Ozarks hills with a 1997 PowerQuest 380 Avenger.

Sounds like somethin was wrong with it, no comparison in towing with a diesel vs gas. Any of the gas trucks are gonna get horrid mpg. Had a 98 dodge 3500 DRW V10, great truck never a problem. But only got 13-14mpg empty on the highway 11 @ best around town 7-8mpg towing the boat at 75-80mph. Can be found much cheaper than the Chevy's.

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Like I said , its definitly no 6.7L cummins, or 6.7L Ford diesel when it comes to towing power. But generally, they are solid reliable engines, that last a long time. They are known for intake gasket leaks, injectors around 100k miles. But, cheap and easy to repair. I installed a set of takeout LS1 injectors I scored for 65 bucks that were like brand new, slapped some intake gaskets on it, new fuel pump, new distributor, wires, plugs Total parts cost was under 300 bucks for all that lol.[ATTACH=CONFIG]520445[/ATTACH].

I have a Flat deck buddy, I wouldnt buy a 6.0 .. and at least my tuned 7.3L got close to 16-18mpg empty highway. I could enjoy the truck during the non boating months.. with this gas hog I cringe any time I have to take it anywhere.
Its the only truck that registers worse gas mileage if you let it sit idling for more than 5 minutes. Without a doubt I`m going back to a Diesel.

I had 2 2500 Suburbans (first one was stolen).Great tow vehicle and got 13mpg consistently in both.8-9 towing a 35 Fountain.

Went to a 6.4 F350, after getting the Fastech and as nice as the Suburban was, it's still not a diesel. If you're towing a boat like mine, yes the Burb will do it, but not anywhere as well as that truck.

My $.02...

Put over 100 k miles on an 01 2500 LB CC. 10 miles per gal.Period! great truck other wise. Like clock work put 20 gal in tank ck trip odometer 200 miles.
And a qt of oil every 1500. Don't for get that.

I now have a 3500LS Regular Cab Dually with the 8.1 and Allison. I like the truck, its about 11-13 Highway and pulling the boat 8-9. In NYS gas is around $3.65 and Diesel is pushing $4.45. I had a diesel before and yes it had a little better hill towing power, and the gas mileage was a bit better, but unless you are towing a lot, maintenance, fuel, initial price, etc, doesn't always make sense. However it is getting harder to find decent mileage, good condition 8.1s since they have been discontinued for a while. The Allison transmission on either package is great for towing boats.

I've got an 2002 3500 dually crewcab 8.1. 5 spd allison...About 11 mpg highway light. Depending on load, mpg as low as 7 or so. If I was doing a lot of long distance towing I'd own a diesel ..But I don't, so I won't.I just don't like pulling up to the diesel pump and having to step in oil-sorb .And it seems no matter what, a little diesel fuel will get on me from the fuel soaked nozzle. My wife doesn't like the smell and neither do. Say what you want but I like my 8.1 gas