6.0 vs. 5.3??

January 9, 2002

I'm very disappointed in the torque of the 5.3 and by this summer I'll be pulling about 8000 lbs a couple times a month. I've already found out it will kill my present truck and maybe me too. Has anyone actually put some hours in with both motors...6.0 and 5.3? Gas mileage is also a factor so I'd rather have some torque than 4.10's.

AirForceAngler · January 9, 2002

Well, the first question you are going to have to answer is: do you want to pull 8,000 lbs safely or get good mileage? Also, what is your idea of good mileage? You'll get about 16 on the highway, empty with a 6.0. That's pretty good when you consider what a 350 got 15 years ago with less power than is available now. 8,000 lbs is getting into the 3500 range of trucks and 8.1L or 6.6 diesel. How often are you going to be towing and are there many hills? I had an S-10 once that said it was rated at towing 6,000 lbs, but I'd never do it. I like to have a little lee-way in that area.

Shaners · January 9, 2002

Bill, I have had both motors. Your '99 is down 15 HP to the 5.3L I had in the '00 Silverado with 3.73's (270 vs.285 hp). I currently have the 6.0L in my HD with 4.10's.

My gas milage is terrible no matter what I drive because everything is a short trip, but I'll give you the numbers.

The best milage I had gotten with my 5.3L was 16.5 mpg's. The worst was about 10 mpg's.

The best milage I have gotten with the 6.0L is 14 mpg's and the worst was 7.6 mpg's (see my post in the HD forum and it'll explain why).

Overall I figure I lost about 1.5 - 2 mpg's, but my truck is now a full crewcab and weighs well over 1/2 ton more than my '00 Silverado did.

My 6.0L isn't broken in yet and I think the milage will get better.

If you want 6.0L and 3.73 gears you will have to get an 8600 GVW truck like the 2500 series or the 1500HD. The 2500HD with the 6.0L is only available with 4.10 gears.

People with the 6.0L and 3.73's are claiming 16.5 mpg's on the highway and 13 around town. I expect to be able to do 1-1.5 mpg's less than that...

I tow an 8000 lb '32 travel trailer occaisionally and the 6.0Lw/4.10's does very well. On the interstate I never have dropped below 58 mph while towing, and I get around 8 mpg's while pulling that big parachute on the hilly roads of Western PA.

The difference in mpg's over 10K miles is approx 65 gallons on the highway for the 2 combos. That's really only a couple of tanks a year, so don't let it scare you away from the 4.10's. I was very impressed with my truck...

Sorry for the long reply...

January 10, 2002

Thanks for the replies....decisions...decisions. Shaners, your mileage sounds good to me and I did read your other thread. From a standing start up a fairly steep hill, how does your 6.0 do getting that 8k moving? My 5.3 & 3.73's do OK on the road and and the hills that I would normally run but getting started on a hill is a killer. I think my old piece of poo poo F250 with a 460 spoiled me with torque but it's best was 11 mpg in the heat of summer and down hill.

HillHound · January 10, 2002

Bill,

Is a 3/4 ton truck with a diesel a possible option for you? If mileage is a big concern the diesel may be the best way to go. Almost without a doubt it will blow the other engines away in mpg and no doubt the torque will be great. My opinion is that if I had to pull 8000lbs twice a month I would have a 3/4 ton diesel in a heartbeat! The 1500 will do it occasionally, but like you said: it's going to be hard on your drivetrain if you pull it regularly. Like you said: decisions, decisions!

Kansas Kid · January 10, 2002

I have a question for you regarding the trailer. What exactly are you going to be pulling? A 5th wheel or travel trailer will pull considerable harder the a car trailer or a flatbed gooseneck trailer.

But regardless of what you are pulling, I'd say the 6.0 and 4.10 gears would be a good combo. You do not want the 3.73 gears with a 6.0 pulling this kind of weight if you can avoid it. With the 3.73 gears its quite possible you would get worse mileage when pulling, as the motor is going to be out of its power range in OD, and will spend alot of time in D. I do not think you really need a big block or especially a diesel for this kind of pulling. Quite honestly the only time a diesel becomes and advantage is when pulling over 10,000lbs and pulling it quite regularly (as in every week, or on very long trips). Now don't get me wrong, as I absolutely love diesel engines. But they aren't suited for every application. They want to be worked hard and worked often. I wouldn't want to pay the addition $6000 up front for something I couldn't use to it extents....

Jpshostr · January 10, 2002

I'm going to say the 6.0L is the best bet concerning motors here. Get the 4.10 gears in it, they shine in getting loads moving. This 8000 pound trailer sounds to be a regular thing that you are expecting, better set up your truck for it. Since the 6.0L isn't available in the half tons, step up to the 2500 platform, but I don't think the 2500HD is needed. You have a choice of reg cab longbed or a ext. cab shortbed with the 2500. You also get the 4L80E tranny which would be a better one over the one that comes in the 1500s.

Shaners · January 10, 2002

Wef,

My 6.0L does a much better job pulling this trailer than the Triton 5.4L F*rd F250 I had for about a year.

It just squats and goes when I step on the gas. The brakes are excellent too. I actually pulled the trailer home without any electric brakes (about 10 miles) so that I could work on it and I was surprised to see how well these brakes are!!!

On the interstate at 65-70 mph, I was running about 3000-3200 rpm most of the time. I used tow/haul mode and left the truck in OD as the manual states!!! On the flat the truck would actually shift into OD and lock the converter and would cruise along no problem at 70 plus!!!

My travel trailer has a slide out, so it sits extra high to allow for all the extra frame etc... I'm not very aerodynamic!!!

January 10, 2002

Thanks again guys. The 8000 lbs. is a JD skidloader and a HD 2 axle trailer. It scaled at 83xx before the weights were taken off the loader. The truck doesn't get enough miles to justify a diesel but after researching Edmunds and KBB that 8.1 is starting to look good. It looks like nowadays you can get all the creature comforts in the HD trucks too. Next Monday the Sierra is going in for the seatbelt and brake line recalls and also for them to tell me the Autotrac is supposed to hop-skip and jump around corners When I'm there I'll test drive an 8.1. So much for the fuel mileage.

Shaners · January 10, 2002

The big block is a great idea, and milage isn't a whole lot worse than my 6.0L. The advantages are you get the Allison Tranny!!! The disadvantages are, you have to pay for the Allison tranny!!!

CMNTMXR81 · January 10, 2002

At least with the 8.1 though, you only pay $850 to upgrade vs. $4,200 for the Duramax.

I used to tow all the time with my 97 Tahoe (Vortec 5700) and pulled around 6,000lbs with ease. So the 6.0L or above shouldn't have a problem.

Shaners · January 10, 2002

At least with the 8.1 though, you only pay $850 to upgrade vs. $4,200 for the Duramax.

You are right cmntmxr. The 8.1L is a very reasonable cost... but the Ally is expensive (but worth it...)

CMNTMXR81 · January 11, 2002

I'd still pay for it if it were an option (well techincally it is but I'm refering to LT trim packaged trucks) and I were upgrading to either the 8.1 or Duramax.

January 12, 2002

What is the big advantage of the Allison over the GM 4 spd. auto? I like the tow/haul mode and if it had a slightly lower low gear it would be almost OK. How many speeds is the Allison? Right now I'm leaning towards an 8.1, 3.73 and GM auto.

siume99 · January 12, 2002

I'd go diesel if you are worried about mpg and torque. Is there any way to the the 6.0L HO Cadillac engine (LQ9)? 345hp and 380ftlb torque!!!!! The Cadillac Escalade is AWD and gets 12/16mpg, 4L-60E-HD tranny and tows 8200lbs with a 3.73. The EscaladeEXT tows 7900lb. I WANT ONE! I can deal without the bells and whistles. I just want the engine and tranny!!!!