Looking for a dually should I go 454 or 6.5 diesel

[cartman]

Looking for a dually extended cab 4x4, should I go with a 454 or 6.5 diesel. interested in gas mileage. I currently have a 1990 regular cab 4x4 2500, with 5.7 throttle body and 400 tranny ( 410 gears ) it is ok around town but is HORIBLE on the highway due to the no overdrive and high gear ratio. I am wondering what to expect with a vortec 454, and overdrive? since diesel is just as expensive as gas ( more here) if the 6.5 dosen't get a huge differance in mileage, it's probably not worth it. Just looking for some opinions Thanks

[cayoterun]

We use a '97 Chev crewcab 454, automatic, to tow our 26' 8500# travel trailer. Straight interstate driving, no trailer it gets about 10.5mpg. Last summer, in 8,000mi combined towing and no trailer, it averaged 8.5mpg. The truck has 132,000 on it/w 4.10 gears. We never run over 60mph towing.
Cayoterun

[72freak]

In my experience a 6.5 has not gotten the best fuel mileage.......

If those were my 2 options I would throw in the towel and go with a Powerchoke?!?!?!?! LOL

[cartman]

Wow I figured a 454 would get closer to 12 or 15 unloaded. Any one know what the 6.5 diesel gets?

[72freak]

Originally Posted by cartman

Wow I figured a 454 would get closer to 12 or 15 unloaded. Any one know what the 6.5 diesel gets?

It has been my experience 12-15 for 6.5 AND 8-10 FOR THE 454. THIS WILL DEPEND ON YOUR FOOT AND THE TRANS. AND THE REAR END. Also 2 or 4 wheel drive.

Now evryone will chime in eventually and Im sure you will get 6.5 #s ranging from 10 to 18 and 454 #s ranging from 8 to 14.

Its not uncommon for empty 2x4 diesels to get 18-20mpg with your foot out of it.
A 454 will never see those #s

[rotgg]

454

[68K20 x Drill]

A 6.5 will always get better mileage than a 454, but load them up, and the 454 will burn almost twice the gas.

[crews]

Originally Posted by 68K20 x Drill

A 6.5 will always get better mileage than a 454, but load them up, and the 454 will burn almost twice the gas.

I completely disagree with this statement.

I used to have a 94 Crew Cab Dually, 2wd, 454, slightly lowered and it got consistently 13-14 unloaded at 70mph and 10-12 LOADED at 70 with the AC on. It never mattered what was on the trailer. I have an 18' open car trailer that I have pulled from coast to coast with this truck.

At the time I owned this truck, my uncle owned a 95 X-cab dually with a 6.5. It got 17-18 unloaded and it dropped like a ROCK when loaded with a trailer. It went to the 10 or less range depending on which trailer he pulled. The biggest problem was that when it came to running down the highway, he couldn't pull any grades and maintain speed. I had to pull over to let him catch up....

IMHO- the 6.5 diesel has NO redeeming qualities over a 454, even a pre-vortec one.

Things to consider-
If you are in the middle of no-where Arizona on a Sunday afternoon, and you break down, you have a far betetr chance of the local parts house having big block parts in stock. Diesel parts are expensive and are not readily stocked.
( My uncles truck went through 4 injector pumps during his ownership. These are not cheap.)

Fuel availability- I can tell you from first hand experience- Diesel availability in remote parts of the country is hit or miss. I have had some close calls in Iowa on a Sunday trying to find Diesel fuel.

General Maint.- EVERYTHING is more expensive on a diesel. Oil changes-almost double the capacity and the oil filter itself isn't cheap. Plus, every other oil change, you need to do a fuel filter. This is a MUST if you want the truck to last. Avg oil change cost $75-100 depending on what brand filters you use.

I also owned one of those "great" power strokes and I was NOT impressed. It was a 7.3/ 6 speed with 4:57 gears in a F-450 4wd crew cab and it got HORRIBLE mileage. 10-12 unloaded and around 6 with a load on it. And it was the weakest pulling truck I have ever owned with the exception of the first 25 feet. In low gear, it would walk out of anything, but after that it was all downhill.


At the end of the day- I will take a gas burner any day over a diesel. The money just doesn't wash for me. The only place i have seen diesels outperform a gas motor is in mileage longevity and even there I will take my chances. I have had 150K plus on several big blocks ( and even the 6.0 I just sold) and never had any trouble with them mechanically.

Again- this is just my opinion from many miles of experience towing with both types of motors.

[cartman]

I am not really worried about repair costs, as I do all my own work. I also get parts for deep discount. I know all about the injector pump issues with the 6.5 I have replaced tons of them for our customers, There is a place close by that rebuilds them Very happy with their work.That is all that seems to go wrong with them ( as long as they are maintained ). Usually it is the PMD ( pump module driver ) that black box on the side of the pump. Most people just replace the entire pump, which does fix it, but most of the time it just needs the pmd. Any How I have only owned trucks with small blocks, except for a old bucket truck with 454 that got gallons to the mile. I have never driven a 454 or 6.5 for long peroids of time to get a feel for mileage, power while loaded, etc. Every one around here is either a dedicated Diesel guy or a Gas guy. Just trying to get some opinions / facts to weigh out the two. I will be running it just between Newyork and Maine so getting Diesel fuel is not much of a problem . I will be looking for a truck with a 4L80 tranny, and 4x4. Thanks for all the great comments so far!

[crews]

Yeah everyone has their reasoning for their preference. I just know that I have had horrible experiences with diesel trucks, both with mileage and reliability.

Bear in mind that you also don't have to worry about gas gelling up on those cold northeastern winters either!!

[72freak]

[QUOTE=crews;2549722]Yeah everyone has their reasoning for their preference. I just know that I have had horrible experiences with diesel trucks, both with mileage and reliability. QUOTE]

I agree completley if you are talking aboput 6.2/6.5.......now late 7.3's and Cummins I have had geat luck with.

[crews]

[quote=72freak;2549746]

Originally Posted by crews

Yeah everyone has their reasoning for their preference. I just know that I have had horrible experiences with diesel trucks, both with mileage and reliability. QUOTE]

I agree completley if you are talking aboput 6.2/6.5.......now late 7.3's and Cummins I have had geat luck with.

Nope- I HATED my 7.3..... It was the worst engine I have ever had the misfortune to own. WEAK WEAK WEAK.

I can say that I have NO experience with the new duramax, but the Cummins diesels are OK... My brother had one of those and he only had to replace the lift pump ONCE ( at 30K something miles)

[cayoterun]

I forgot to mention that the mechanic that maintains our '97 said I needed new fuel injectors. Truck runs fine. I just haven't got around to spending the $800 he said they cost. That might help my mileage some. It's two wheel drive.
I just like the old brutes
Cayoterun

[chrisk1500]

I would put my 6.5 up against a 454 any day. I will out tow it, out accelerate it, and out economy it...

If you are serious about a 6.5 you should check out dieselplace.com

There are a ton of us over there who know these engines inside out and can get you moving in the right direction.

[jkaylor68gmc]

my dad has a 96 3500 with a 454 5-speed combo and when we pulled my 51 to Hunstville, it took a little less than a tank.

We used my boss's F-350 7.3 and it took a tank and a half. Plus the gas is cheaper than diesel!

[chrisk1500]

Originally Posted by crews

Things to consider-
If you are in the middle of no-where Arizona on a Sunday afternoon, and you break down, you have a far betetr chance of the local parts house having big block parts in stock. Diesel parts are expensive and are not readily stocked.
( My uncles truck went through 4 injector pumps during his ownership. These are not cheap.)

Your uncle's mechanic doesn't know what the hell they are doing then.

General Maint.- EVERYTHING is more expensive on a diesel. Oil changes-almost double the capacity and the oil filter itself isn't cheap. Plus, every other oil change, you need to do a fuel filter. This is a MUST if you want the truck to last. Avg oil change cost $75-100 depending on what brand filters you use.

The oil filter is about $5 at the dealer. Cheaper elsewhere. Capacity is not that much different. Maybe a litre or so.

Average oil change for my 6.5 is about $20. I only use Delco filters.


You need to realize that he is comparing a 6.5 to a 454....no mention of a powerjoke....

[cartman]

Originally Posted by chrisk1500

Your uncle's mechanic doesn't know what the hell they are doing then.



The oil filter is about $5 at the dealer. Cheaper elsewhere. Capacity is not that much different. Maybe a litre or so.

Average oil change for my 6.5 is about $20. I only use Delco filters.


You need to realize that he is comparing a 6.5 to a 454....no mention of a powerjoke....

Yes, I have no intention of buying anything but a chevy/gmc. I know that they are not really too much to maintain .I do work on these. yep oil changes about 20$. I do like the Duramax ( after they solved the injector problems) but they are too new ( out of my price range ) and I just like the 89-2000 body style They feel like a heavy well built truck when you drive them. Also a Duramax out of waranty is going to be expensive to repair in parts alone. Although a friend of mine has one with close to 200k with no problems. Any way my goal is to find a 95 or newer extended cab, dually, 4x4 , 4L80 . If I could get 5 more miles per gallon it will be the 6.5 . The prices on these old used trucks is not much different weather it's gas or diesel.

[chrisk1500]

Get the diesel....if you can do your own wrenching you will be happy

Check out Heath Diesel for reliability and performance modifications for the 6.5...

[crews]

Originally Posted by chrisk1500

Your uncle's mechanic doesn't know what the hell they are doing then.

You need to realize that he is comparing a 6.5 to a 454....no mention of a powerjoke....

Actually you are correct I was speaking of my experience with the Ford diesel.

But I also see that your diesel is FAR from stock. You can do just as well with a gas motor for far less money.

as far as my uncles mechanic- It was the GM dealer.

It seems that you are obviously happier with diesels. I myself am happier with a gasser. You know what they say about opinions.....

YOU need to realize that he was asking about personal experience and OPINIONS about the difference between the two. Since I have had experience with both, I offered my OPINION.

I have not had good experince with a diesel powered truck and I can pretty much guarentee that I have hauled more weight and more miles than the average person on this board. Dollar for dollar I will still take a big block.

I guess the best part of this is that I know that you won't be bidding on any gas powered trucks that I am bidding on on E-bay....

[chrisk1500]

My diesel is far from stock. Total cash invested in my trucks is under $10 000 dollars. This includes the $7500 that I paid for the truck itself. Doing the math puts my mods at about $2500.

Find a 6.5 in the States for about $4000 and add the same mods I have and you are looking at about $6500....tons of truck for a little bit of cash.


The GM dealer was notorious for throwing IPs at the 6.5 when infact the actual problems were the usual culprits of the LP, OPS, and PMD. All it would have taken was a tech with some good training instead of the 'lube' guy to take a look at the truck. Not your fault, GM's fault.

Your information is about third hand.

I have experience with the 454 AND the 6.5. Both GM trucks.

I stand by my opinion that the 6.5 will outdo the 454.

In fact, Diesel Power Magazine did a comparison between the two not too long ago.

The stock 454 did win the contest as far as power goes and the stock 6.5 won as far as economy goes. Now add on the mods that I have to increase the HP and TQ to a stock DMAX LB7 and now the 454 does not even stand a chance.

And no, I won't be outbidding you on ebay....

Real trucks don't have sparkplugs

[cartman]

Just wondering what your mods to the 6.5 have done to mileage???

[chrisk1500]

Up by about 2 mpg unloaded....I am not a good person to ask because my typical cruising speed is 80 MPH (outside of the 6.5 diesel's sweet spot of around 2200 RPM).

Even at those speeds I am getting a consistent 17 MPG with winter fuel...should be closer to 18.5 with summer diesel.

There are a few guys on dieselplace.com with duallys and 4.10 gearing in the very high teens cruising around 55 - 65 MPH.

[cartman]

Yes I have a heavy foot also, like to cruse at 75/80 on the interstate. I was looking at the diesel place seems to be a lot of knowledgable diesel people there.

[Scott68-93-97]

My 93 6.5 turbo w/nv4500 gets 17-20mpg 15 at the lowest while towing about 9000 lbs thats heaviest Ive had on it, Ive also had over 2 tons of payload in it before with good mileage, plenty of power 80 mph while towing( not that you would want to but the truck doesn't have a problem doing so), empty it can stay in OD all the way down to 35 mph and accelerate back up no problem. Iv'e got a Magnaflow 3 inch turbo back exhaust on it thats all, that opened a lot of low end power. The 93 is all manual no cpu no electronic pump with the lame optical sensor to go out, there is a company that sells a coversion to the older DB2 pumps from the newer DS4's that fixes that and you can move the pmd off top of motor and install a manual wastegate control. Cheap things fix all the problems with the 94-2000 6.5's

And if you compared my 93 6.5 to a 93 cummins or poopstroke it has a lot more power, until the late 90's the powerstroke and cummins were not all that great in the power department granted I do believe the cummins is a much more stout motor but it was also designed for heavy duty use not light duty use like the 6.5 was designed for

[jugernot]

Well it you went with the diesel you could change it over to BIO DIESEL and make you exhaust smell like french fries.