5.7 vs 6.4 towing

So my dad started a hauling business. Has a 6x12 dump trailer he rents out. Will haul gravel, sand, mulch, construction debris. Max probably around 10,000 pounds. Don’t want a diesel due to extra cost right now and extra fuel cost.
We found a 2017 with the 5.7. I have a 2016 with the 6.4 and love it. I run a construction business and haul similarly to what he does.
His 2021 1500 has the power but is struggling with the suspension when hauling heavy. Will the 5.7 be sufficient for this or should we keep searching for a 6.4 truck.

Having owned both my vote is a 6.4L truck.

If you plan on hauling things for a living, go for 3500 w/6.4L you never know when you'll need to load the bed and dump trailer

Having had both, agree with previous comments. HD, 6.4, preferably 4.10’s.
I believe a 2500 weighs about 2k lbs more than a 1500 and I assume most of that is frame and suspension.

Hes open to 3500 it’s just a matter of finding a deal in this crazy market. I’ve loaded my 2500 down a lot and it’s handled it fine but I guess a 3500 would do better. I used to haul 2000+ Pounds of tools in the back plus pulled my dump trailer. It did squat though.

Irishthreeper said:

Having had both, agree with previous comments. HD, 6.4, preferably 4.10’s.
I believe a 2500 weighs about 2k lbs more than a 1500 and I assume most of that is frame and suspension.

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Yep that’s exactly the need for the upgrade. His truck will do it but handling and stopping suffer. It’s just gonna wear it out too.

A 2500 will do fine but a 3500 would be insurance for future upgrades. But in my opinion a 1500 is a no-go. It might be ok for an occasional trip but if it's going to be a common thing that will be alot of wear and tear on a 1500. You might be at 95% capacity on a 1500 but only maybe 60-70% on a 2500. For most 1500's 10,000 would be overweight anyway unless you have the 3.92's, which are pretty hard to find nowadays.
The 2017 5.7 you found, is that a 2500? If so I think you would be able to get by with that but if it is a 1500 then walk away.

The 5.7 only has a 9000lb GVWR while the 6.4l gets the 10000 GVWR. The 6.4l also has more GCWR.

The 6.4l is a Big Gas Engine a true HD Engine...the 5.7 is just tuned for HD use.

The 2014 and newer truck has many upgrades over the older ones.

With this crazy price deal we got going...you may be able to get a better deal on a new truck...if you can find one.

dhay13 said:

A 2500 will do fine but a 3500 would be insurance for future upgrades. But in my opinion a 1500 is a no-go. It might be ok for an occasional trip but if it's going to be a common thing that will be alot of wear and tear on a 1500. You might be at 95% capacity on a 1500 but only maybe 60-70% on a 2500. For most 1500's 10,000 would be overweight anyway unless you have the 3.92's, which are pretty hard to find nowadays.
The 2017 5.7 you found, is that a 2500? If so I think you would be able to get by with that but if it is a 1500 then walk away.

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He has a 2021 1500 now. He is looking at buying a heavy duty. We are not wanting to buy another half ton. Sorry if you miss understood.

These guys know their $hit. Take their advice.

Thx for all the input gents.
My pulsar is inbound and hoping it gets here by mid week.
I'm towing Thursday over a route I've taken regularly will report back on any changes the pulsar brings.RB

Wrong thread...oops

If he is hauling only 10k, then I would stick with the 2500 depending the laws, taxes, and fees in your area especially for a commercial business. That is the reason why the 2500 is limited to 10k GVWR(and subsequently a lower payload) due the added taxes, and requirement placed upon vehicles with a GVWR over 10k. In many states, you may have to pay hundreds more per year with a 3500 truck that has a GVWR over 10k and be required to have a special CDL if it is used for commercial use.

The 2500 has the exact same parts as the 3500 except for the rear suspension which will handle within 500 lbs of the 3500. In bone stock form, my truck squatted within a half an inch of a friends 3500 with a 14k trailer with a 2,500 pin weight. After installing sumo spring rebels, it squatted less than the 3500 even with a leveled front suspension.

In regards to the 5.7L vs the 6.4L. If power is more important, then get the 6.4L. If cost is more important, then get the 5.7L. Due to added cost of maintenance cost and initial cost of the 6.4L, the total cost of ownership will be more on the 6.4L the longer you own which cannot mostly be recouped in fuel efficiency and/or resale like the diesel can.

Below is a total cost of ownership(minus repairs) I made along time ago for our fleet at work. I updated the cost of fuel to current prices. Resale is a little higher right now(especially for the diesel), but I left it to resale values of several years ago since it is not that much of a difference. It also has the cost of 87 and 89 octane since 89 octane is recommended for both the 5.7L and 6.4L especially in the commercial towing duty cycle you will be using it in.

Hope that helps you make a decision!

EDIT: I can send you the Excel file below that will auto populate your total cost depending on your inputs for the cost in your area. Just PM me with an email address and I will send it to you.

OP, in regards to the fuel cost of a diesel comment, it is actually the opposite of what you stated. Not trying to get you to buy a diesel or turn this into a diesel vs gas thread, but the higher the cost of fuel goes, the more it is in the favor of diesel.

For example, the current average mpg on Fuelly.com with millions of miles and thousands of fill-ups tracked is 15.5 mpg for the Cummins and 12 mpg for the 6.4L and 5.7L Hemi. With local 87 octane at $4.29 and diesel being $4.99, that would mean a cost per mile for the Hemi's would be $.36 per mile and the Cummins at $.32. That is a difference of $.04. Diesel would have to be at $5.55 here to have the same $.36 cost per mile.

As diesel and gas prices decrease, then so does the differences in cost per mile. So if 87 octane was one dollar less at $3.29 and so was diesel at $3.99, then the difference in cost per mile would be $.02 instead of $.04. If 87 octane was two dollars cheaper at $2.29 and diesel was $2.99, then cost difference would be $.00 per mile. So as fuel prices go up, then it favors diesel. As they go down, then it favors gas which was the opposite of what you were saying.

SouthTexan said:

OP, in regards to the fuel cost of a diesel comment, it is actually the opposite of what you stated. Not trying to get you to buy a diesel or turn this into a diesel vs gas thread, but the higher the cost of fuel goes, the more it is in the favor of diesel.

For example, the current average mpg on Fuelly.com with millions of miles and thousands of fill-ups tracked is 15.5 mpg for the Cummins and 12 mpg for the 6.4L and 5.7L Hemi. With local 87 octane at $4.29 and diesel being $4.99, that would mean a cost per mile for the Hemi's would be $.36 per mile and the Cummins at $.32. That is a difference of $.04. Diesel would have to be at $5.55 here to have the same $.36 cost per mile.

As diesel and gas prices decrease, then so does the differences in cost per mile. So if 87 octane was one dollar less at $3.29 and so was diesel at $3.99, then the difference in cost per mile would be $.02 instead of $.04. If 87 octane was two dollars cheaper at $2.29 and diesel was $2.99, then cost difference would be $.00 per mile. So as fuel prices go up, then it favors diesel. As they go down, then it favors gas which was the opposite of what you were saying.

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Awesome analysis, thanks for posting. When I was younger I'd get fired up enough to do this sort of compare. Very useful.

SouthTexan said:

OP, in regards to the fuel cost of a diesel comment, it is actually the opposite of what you stated. Not trying to get you to buy a diesel or turn this into a diesel vs gas thread, but the higher the cost of fuel goes, the more it is in the favor of diesel.

For example, the current average mpg on Fuelly.com with millions of miles and thousands of fill-ups tracked is 15.5 mpg for the Cummins and 12 mpg for the 6.4L and 5.7L Hemi. With local 87 octane at $4.29 and diesel being $4.99, that would mean a cost per mile for the Hemi's would be $.36 per mile and the Cummins at $.32. That is a difference of $.04. Diesel would have to be at $5.55 here to have the same $.36 cost per mile.

As diesel and gas prices decrease, then so does the differences in cost per mile. So if 87 octane was one dollar less at $3.29 and so was diesel at $3.99, then the difference in cost per mile would be $.02 instead of $.04. If 87 octane was two dollars cheaper at $2.29 and diesel was $2.99, then cost difference would be $.00 per mile. So as fuel prices go up, then it favors diesel. As they go down, then it favors gas which was the opposite of what you were saying.

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Not arguing your point but diesel is about $1.20 per gallon more than 89 here in western PA (.90 today actually. 5.99 vs 5.09) but a few days ago it was 5.99 vs 4.79

dhay13 said:

Not arguing your point but diesel is about $1.20 per gallon more than 89 here in western PA (.90 today actually. 5.99 vs 5.09) but a few days ago it was 5.99 vs 4.79

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Yeah, with that kind of difference the 5.7L would still be the cheapest, but the 6.4L would edge out the Cummins by about five dollars over the course of 100k miles according to my chart.

SouthTexan said:

OP, in regards to the fuel cost of a diesel comment, it is actually the opposite of what you stated. Not trying to get you to buy a diesel or turn this into a diesel vs gas thread, but the higher the cost of fuel goes, the more it is in the favor of diesel.

For example, the current average mpg on Fuelly.com with millions of miles and thousands of fill-ups tracked is 15.5 mpg for the Cummins and 12 mpg for the 6.4L and 5.7L Hemi. With local 87 octane at $4.29 and diesel being $4.99, that would mean a cost per mile for the Hemi's would be $.36 per mile and the Cummins at $.32. That is a difference of $.04. Diesel would have to be at $5.55 here to have the same $.36 cost per mile.

As diesel and gas prices decrease, then so does the differences in cost per mile. So if 87 octane was one dollar less at $3.29 and so was diesel at $3.99, then the difference in cost per mile would be $.02 instead of $.04. If 87 octane was two dollars cheaper at $2.29 and diesel was $2.99, then cost difference would be $.00 per mile. So as fuel prices go up, then it favors diesel. As they go down, then it favors gas which was the opposite of what you were saying.

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While this analysis is good, it does leave out the very important "return on investment" answer. Sure, if the price of the gas Hemi and diesel Cummins trucks were the same it definitely makes sense to go diesel when comparing fuel costs. However the diesel truck is going to cost a good bit more. Doing a quick search on something like Kelley Blue Book on used car values on the exact same truck except for the engine, the diesel version will cost you an additional $8,000 - $9,000 in initial purchase price. If you are only saving $0.04 per mile on fuel that means you would have to drive 200,000 miles before you even broke even on spending the additional money to buy a diesel. Not saying that diesels are bad and they have other advantages when towing, but I wouldn't base the decision on fuel cost savings alone.

62Blazer said:

While this analysis is good, it does leave out the very important "return on investment" answer. Sure, if the price of the gas Hemi and diesel Cummins trucks were the same it definitely makes sense to go diesel when comparing fuel costs. However the diesel truck is going to cost a good bit more. Doing a quick search on something like Kelley Blue Book on used car values on the exact same truck except for the engine, the diesel version will cost you an additional $8,000 - $9,000 in initial purchase price. If you are only saving $0.04 per mile on fuel that means you would have to drive 200,000 miles before you even broke even on spending the additional money to buy a diesel. Not saying that diesels are bad and they have other advantages when towing, but I wouldn't base the decision on fuel cost savings alone.

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As you can see in my chart above and in the scenario you just stated where a used diesels will cost $8,000-$9,000, it will also be worth $8,000-$9,000 more through the life of the vehicle so it is resale AND fuel savings that bring their total cost down. Just like a Laramie trim demands $9-10k at purchase over a Tradesman, so does it at resell. The argument that you ONLY recoup the cost of the diesel in fuel is only valid if the value of the diesel was the same as the value of the base engine throughout the life of the vehicle which is not the case.

You will also recoup most of the additional money spent on the 6.4L over the 5.7L too(which I believe was like $1,200 back then). However, due to the additional cost of maintenance on the 6.4L from the special oil, the cost will increase with the 6.4L over the 5.7L the longer you own it as to where the cost will decrease with a diesel the longer you own it. Then when you trade the diesel in or sell it at 100k or 200k miles, you can sell it for $8,000-$9,000 more than you could with the base engine because the value of the truck is worth more. Then you will recoup the rest of that money not saved through fuel. Which with current prices where I live, would be at 155k miles and I am actually not too far from that.

Again, not trying to start a diesel vs gas thread. Just wanted to correct a misunderstanding.

A note of interest for the above analysis - all Gen III Hemi engines benefit from use of special oil to reduce the possibility of valve lifter and cam destruction. This engine design is the only street gasoline engine I am aware of that benefits from highly-additized oil. Cummins diesel doesn't need a band-aid oil - it just needs more oil (for holding soot in solution).