Experience with the GM 6.6 gasser? - Page 2

Martin Q. Blank

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In reply to ChoppinDs40 • 9:07a, 10/28/25

Quote:
You've gotta burn ALOT of fuel to make up for 12k in costs.

I'm not sure you would ever make it up. Diesel is ~20-25% more expensive than gas. And it gets ~20-25% better mpg. So it's a wash.

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ChoppinDs40

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In reply to Martin Q. Blank • 12:07p, 10/28/25

AG

I think the big diesels get better than 20% mpg over the big gassers.

I know guys get 18+ especially deleted diesels. I'm getting 13 with the 7.3. That's closer to 40%.

El Gallo Blanco

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In reply to GottaRide • 12:13p, 10/28/25

GottaRide said:
Here is the one I got last week. The first tank got 13.4 mpg. I had a 2016 with the 6.0 that got 12.5. I haven't pulled my gooseneck with it yet but it feels like it will do just fine. I got the custom package and love it.

Great looking truck. Leaning towards same and throwing some 35's and LED's on it.

Martin Q. Blank

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In reply to ChoppinDs40 • 4:59p, 10/28/25

ChoppinDs40 said:
I think the big diesels get better than 20% mpg over the big gassers.

I know guys get 18+ especially deleted diesels. I'm getting 13 with the 7.3. That's closer to 40%.

Title of thread is GM 6.6 gasser, not 7.3.

TSW2012 said:
Lifetime average 14.7mpg

shm5088 said:
Get about 14-15mpg in combined driving.

18 / 14.7 = 22%

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GottaRide

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12:24p, 11/1/25

S

I'm pulling 8 cows today. Averaging just over 8 mpg. It pulls much better than my '16 with the 6.0. I'm very pleased so far. The gooseneck hitch sits a few inches behind the axle by GM's recommendation. I worried about that but it rides great.

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