GM 6.6 & 3:73 gas

[JFF&KRN]

It's Me again;
Just trying to get some updates, that is for the 6.6 Gas GMC, most likely 3:73. In talking to some on the road, the few that have it seem to like it for the most part. Just a little bit differnece from the 6.0 wit a bit better power and maybe a bit better milage. I am spoiled so I think i am goign ot buy me a new truck. just if anyone has updates on the 6.6 gas, that would be great. Thanks to all and have a great day.

[LMagelitz]

Specs I could find:
6.0L gas 360hp@5400rpm, 380 ft-lb@4200rpm
6.6L gas 401hp@5200rpm, 464 ft-lb@4000rpm
6.6L diesel 445hp@2800rpm, 910 ft-lb@1600rpm

Not sure how much you’re towing. We towed a 13k lb Solitude in the rolling hills of Minnesota, Iowa, and South Dakota with a 6.0L gas, and it was an unmitigated disaster, unless you don’t mind a screaming motor. In the Black Hills it was a no-go. The 6.6L gas looks marginally better on specs.

[JFF&KRN]

we're towing 337 rls fifth wheel, loaded for our normal trips, trailer is at 13,500 with full water food etc.
I don't remember the total of all weights, but do remember we are about 6o00 punds below combined.
during our trips, most recently to Colorado, million dollar highway included, we did fine, if you call it struggled, slowere on the big hills. we do have the 2019, 6.0 gas with 4:10. Just with the higher rpm with 4:10, seems to suck the extra gas. Just looking for something a bit better without going diesel.
thanks,

[jpinto02]

So I have had 2 6.0 and now have a 6.6gas(2021 Sierra). Daily driving seems pretty similar. Never towed with the 6.0 much so cant really compare in that aspect. As for towing with my 6.6l it does the job. I pull a 30G at around 11K. I drove from NY through mountains in PA to NJ and got between 5-6 mpg. Keep in mind I have a heavy foot. I think I could have gotten it more in the 6-7 mpg. On flat highway at around 60mph 7-8 can be expected. As for pulling power it has no issue on hills or even passing cars. The RPM's ride high ~4500rpm so you hear it but has no issues doing he job. Was worried about not getting the diesel but now I am glad I didn't spend that extra money. Keep in mind that I am not a full timer either. I am at maybe 10 trips a year with it. Most of the time its a daily driver.

[NB Canada]

I am waiting for a gas Sierra 3500 crew with something other than the 6 speed
Hopefully GM will mat a 10 speed to the 6600 someday

[robmcqueen]

They said the 2024 will have the 10 speed

[Shelby748]

I have 2020 Silverado 2500HD LT, 6 speed, 373 gears. I pull a 2022 Imagine 3100RD, at about 8800 lbs with all of our stuff. We go over the Oregon Cascade Mtns, several times a year. We easily cruise at 60 MPH and pull 6 to 8% grades at 55 MPH at 3000 to 3500 RPM. On an average we get 8 to 10 MGP. Hope this helps you.

[JFF&KRN]

Yepper,
Thanks.
Just still need to decide if i want a truck payment for a few years, without one is really nice.
But then again, maybe better get r done sooner than later.
thanks again everyone! ! !