So, crew cab 2wd dually on gasoline...
Phord's new 7.3 pushrod engine
or
GM's new L8T 6.6 pushrod engine?

Possible gooseneck LQ trailer (40' ish) in the future.

I'd like to hear from those that are pulling with them.

No Dodge.
No Oil burners.

This message has been edited. Last edited by: Goob,

gas with a 40 footer not sure i wanna try that.

Displacement wins....

I pull a 40ft living quarter goose neck with a 2003 Chevy 8.1 lit gas. Trailer weighs aprox 14,000lbs loaded. Unfortunately it only gets about 7 mph towing, it pulls the hills ok, stopping is good.

Back in the late 70s and well into the 90s most all pro racers were pulling Chaparral enclosed trailers with gas powered 454 duallys all over the country and they survived

quote:

Originally posted by Big Steve:
Back in the late 70s and well into the 90s most all pro racers were pulling Chaparral enclosed trailers with gas powered 454 duallys all over the country and they survived

Indeed, and without the hp ratings that today's have. I do wonder about the torque ratings at lower rpm.
Being a chevy guy, it's hard for me to lean toward the cubes that ford is offering. But that would be my choice.

quote:

Originally posted by Big Steve:
Back in the late 70s and well into the 90s most all pro racers were pulling Chaparral enclosed trailers with gas powered 454 duallys all over the country and they survived

I towed a loaded 40' goose all over the SE and more back in the day with my 84 Chev dually, 454 and TH400, 4.10 gears, of course the speed limit was 55, so we cruised around 62-64. The engine/trans held up well in spite of the cruising RPM, it did LOVE gas. Got about 6 MPG.

quote:

Originally posted by "The Bender":

quote:

Originally posted by Big Steve:
Back in the late 70s and well into the 90s most all pro racers were pulling Chaparral enclosed trailers with gas powered 454 duallys all over the country and they survived

I towed a loaded 40' goose all over the SE and more back in the day with my 84 Chev dually, 454 and TH400, 4.10 gears, of course the speed limit was 55, so we cruised around 62-64. The engine/trans held up well in spite of the cruising RPM, it did LOVE gas. Got about 6 MPG.

My '87 Dually only has 50K miles now, but with the grandkids, we need a crew cab, and I hate a f'in motorhome.

Looking at the specs on the new GM 6.6 (4.06" x 3.86") and the Phord (4.22" x 3.97") with similar HP and TQ, I'm thinking the 6.6 might be okay....

It's all gonna be sub 10 MPG anyway no matter what we get, and the '22 Chevrolet is so butt ugly, GMC's not as bad. The interior is where the GMC shines, in my opinion, but the Phord is much easier to order out the way I want it..

Decisions, decisions.

I'm guessing without exposing myself to relentless salesman call backs, that availability might be an issue.

GM RPO Code: L8T
Type: 6.6L V-8 gasoline
Bore & Stroke (in / mm): 4.06 x 3.86 / 103.25 x 98
Block Material: Cast iron with nodular iron main caps
Cylinder Head Material: Cast aluminum
Compression Ratio: 10.8:1
Valvetrain: Overhead-valve, two valves per cylinder, variable valve timing
Fuel Delivery: Direct fuel injection
Recommend Fuel: 87 octane
Power (hp / kW @ rpm): 401 / 299 @ 5200 (SAE certified) Torque (lb.-ft. / Nm @ rpm): 464 / 629 @ 4000 (SAE certified)



Displacement 7.3L, 444.9 cu. in.
Aspiration Naturally aspirated
Cylinder Bore 4.22in / 107.2mm
Piston Stroke 3.976in / 101.0mm
Block Cast iron
Heads Aluminum
Valvetrain OHV; variable valve timing
Compression 10.5:1
Fueling Multi-port fuel injection
Horsepower 430hp @ 5,500rpm Torque 475lb-ft. @ 4,000rpm

Doesn't appear to be enough difference between the two engine wise to make much of, if any difference....The real difference comes when you add in the power train. Converter, trans gears, rear gear, tire size....just because one makes a little more power than the other doesn't mean it will pull better/more/faster.....just like racing it's all in the combo.....

By looking at the HP / measured RPM, the GM engine should be just fine in the RPM range we actually use.
Looking at 3.73 gear on 245/75 17's.

quote:

Originally posted by Goob:
By looking at the HP / measured RPM, the GM engine should be just fine in the RPM range we actually use.
Looking at 3.73 gear on 245/75 17's.

If the GM comes with the Alison transmission, than in my mind that is the only option that makes sense. The 6r140 in the ford is garbage and will not make 125-150k where the alison will go 250,000 miles.

The Allison will go north of 300,000 miles

Don't know much about either engine, but assuming the GM is based on the LSx platform, it has proven to be quite bulletproof over 20+ years and many millions of miles.

TQ obviously more important than HP.
Both peak at 4K RPM.
11 Ft Lb difference is not meaningful.

Neither will get good MPG while towing, but the direct injection and smaller cubes may make a worthwhile difference in fuel mileage for the GM, especially when it is unloaded.

As others mentioned, if the GM includes an Allison trans, that would seal the deal for me...

This message has been edited. Last edited by: FootbrakeJim,

Looks like it's the 6L90 auto for the gasser.

I don't think there are any issues with them, although I find it weird that there is no 1:1 ratio among the 6 ranges.
4.0x:1 low to .67:1 high

The GM "build & price" site is such a f'd up soup sandwich of a site that I almost don't even want to deal with GM.

Show me, REPEATEDLY, 1600+ trucks that are NOTHING CLOSE to the filters I set....

quote:

Originally posted by FootbrakeJim:
Don't know much about either engine, but assuming the GM is based on the LSx platform, it has proven to be quite bulletproof over 20+ years and many millions of miles.

TQ obviously more important than HP.
Both peak at 4K RPM.
11 Ft Lb difference is not meaningful.

Neither will get good MPG, but the direct injection and smaller cubes may make a worthwhile difference for the GM.

As others mentioned, if the GM includes an Allison trans, that would seal the deal for me...

Great points. I didn't see any graphs showing the torque for each at 2500 plus or minus. Long, minor grades can get pretty annoying at 3500 rpm. As many gears as these things have now though, it may not be a big deal.

The 6l90 is NOT a reliable transmission for what you are wanting to do. The converters start eating up 50-60k miles. If you do go that route, have the transmission serviced AT a GM dealer every 50,000 miles. We have rebuilt 150 6l80/6l90s this year alone, every single one of them starts with the converter ****ting the bed. Most of the time we are rebuilding those transmissions between 100-130k miles.

My Duramax only gets 11-13 while towing and probably cost twice as much as a Gasser.....makes me think I could have bought quite a bit of gas for the price difference!

And I might add that DPF just went bad on it (2013 model).

quote:

Originally posted by 329L:
The 6l90 is NOT a reliable transmission for what you are wanting to do. The converters start eating up 50-60k miles. If you do go that route, have the transmission serviced AT a GM dealer every 50,000 miles. We have rebuilt 150 6l80/6l90s this year alone, every single one of them starts with the converter ****ting the bed. Most of the time we are rebuilding those transmissions between 100-130k miles.

Great.
So you're saying add the tube of LubeGard Shudder Stop as soon as I get it?

Well, the good news is...I wont live to see 50K miles.
Took me 19 years to clock 31k on the unit I have now.