Howdy. I searched, not just here on the forum but on Google. Didn't find much, which I thought was odd. Lots on each individually, but not in terms of a comparison.

I'm looking at 2 trucks, for the purpose of towing a gooseneck, about 14,000 pounds.
Truck 1 is a 2001 F-450, 140k +/-, 7.3, automatic, looks clean in the pics, could potentially have the powdered metal rods which would concern me if I start bumping up the power.
Truck 2 is a 2000 F-650, 130k +/-, 3126, manual trans (but don't know specifically what), looks clean in the pics. It had a 20 foot box on it, now it's just a big long frame that I'd shorten. Given the size, I'm assuming it's closer to the 300hp rating than the 175hp rating, but I don't know for sure. If it's not the 300hp, then I'd probably buy the 7.3, so for the sake of this question, assume it's the 300hp.

I'm leaning toward the 650 because the stock rating would be 800 ft/lbs vs 525 for the 7.3. I know there's a lot of performance mods for the 7.3, but I worry about long term reliability once you start bumping it up. I also like the idea of a higher capacity truck (brakes, suspension, etc) not having to work so hard. However, I see lots of posts from people saying the 3126 is gutless, but again, I'm looking at 800 ft/lbs vs 525, so I don't know what their definition of "gutless" is.

I've got decent mechanical skills, but I've never owned a diesel, so I seek any wisdom from the collective that you'd be willing to share.
Thanks

 

What brakes are on those trucks?

Lucas-Girling hydraulic brakes with hydraulic boost are good but expensive to work on.

 

Is the GVW on the F-650 under 26,000 lbs? Otherwise you will need a class A license.

 

If you are in California F450 truck is banned now 2001 7.3l diesel with high GVW

For TOWING I would get the diesel.

 

i think that is a no brainer, you have to work the 7.3 and auto quite hard to tow 14000 lbs, the 650 is meant to do that. The 3126 has way more potential( power) stock, and with a few little mods, can get more power, if needed. Dont be scared of the cat, it is already a HD engine. The auto trans behind the 7.3 would give you more expensive problems than the standard ( probably its an 6 or 8 speed) in the 650.
its easier to put on an exhaust brake on the cat, ( either one is expensive) the 650 allready has bigger wheel brakes, heavier diff etc.
the 650 probably wont be as “comfortable” to drive, but its made to work.
Just my 2 cents

 

I don't know, but that's a good bit to have in my brain as I'm looking. Thanks for the advice

I have a class B and I'm in the process of upgrading to A.

I'm not in California.
They're both diesel.

Exactly what I was thinking, and kinda seemed like a no brainer to me too. But as I mentioned, I know zero about diesels, and you know how the internet is. I asked this question in a 7.3 powerstroke group, and they all think the 7.3 is the greatest thing since sliced bread. Same question in a 3126 group, and they think the 3126 is the best thing since sliced bread. So I look at stuff like B10 and B50 ratings, but it's hard to determine the practical realities of that when you're talking about an engine that was sold to the average consumer versus an engine sold primarily to commercial users.

People with the 3126 seem to either love it or hate it, but then I've got to factor in who is making the comment. I see RV people having problems, but often it's in a vehicle that sits for long periods of time. Or it's in an agricultural vehicle, which may be worked really hard and not maintained as it should. And a lot of people say it's gutless, but are you hauling 20,000 pounds of grain in a C8500 that was kind of a big vehicle for that engine to begin with? I don't know.

The 7.3 people seem to just love the 7.3, but they're always dumping money into "upgrades". I don't know how much of that is just wanting to look cool, but I'm not necessarily interested in huge power at the expense of reliability, which then brings me back to the factory ratings of 525 vs 800 ft/lbs of torque. Then I get weird comments, like somebody who told me the 3126 can't be rebuilt but the 7.3 can. I'm not sure what that means, since neither has removeable liners.

As for comfort, I can work on that. The 650 cab is the same as the 450/350 etc (right?), so I can easily get carpet, and seats, and cupholders, and add power windows or whatever if I really wanted to. And the heavier suspension would keep me awake, right?

I appreciate the .02 cents.

 

With the 7.3L, the transmission is going to be your weakest link when towing 14,000 pounds.

 

The cat- 3126 can be rebuilt, it is a very reliable engine. To do a valve/ injector tune up does take a person with cat experience, but no different than doing trick stuff to the 7.3.
I see someone else added your weak point with the 7.3 is the auto trans, he is absolutely right!
trick up the cab of your new to you 650, all will be good!!
good luck

 

[QUOTE=ispy;21175749]Howdy. I searched, not just here on the forum but on Google. Didn't find much, which I thought was odd. Lots on each individually, but not in terms of a comparison.

PLEASE READ ME
i came across your post on the internet while looking for cheaper Injectors for my 3126...

I own both engines in 2 different trucks. I have a 95 f450 7.3 psd with 5 speed manual trans, which has 367,000 miles.

I also have a 2001 gmc topkick c6500, with a 3126 and allison auto, that i bought with 90k miles, has 148k now. And let me tell you right now.. the 7.3 is hands down better..

7.3 pro's: parts redily available just about everywhere still. Parts are way cheaper. Has twice the power and twice the fuel mileage as the cat. And that's with more than twice the mileage, hauling the same weight. Pulls a hill pretty good.

3126 pros: it's Inline so it's easier to work on. Higher gvwr. It's yellow

7.3 cons: these engines are getting old. They need maintenance just like everything. I've done my fair share of sensor replacement and diag/research. They leak oil worse when you fix the oil leak. You will replace glow plugs. Parts aren't what they used to be, you'll be replacing things a couple times before you get one that works for a while.

3126 cons: gets about 7mpg loaded or unloaded. Pretty slow for being a high hp government motor, especially compared to the 7.3. Slows down to about 50mph up a steady grade. 148k and needs injectors and probably a heui pump for safe measure. Injectors are about $400 a piece. $800 from local cat. Parts are difficult to find and very expensive.

Honestly depends on what your doing and looking for. I cant lie the cat has ben fairly good to me the past 48k miles. I change the oil every 6k with Rotella 15w40 and use only cat filters. Besides having half the power and fuel mileage as the 7.3 it's ben really reliable.

But ive found that ive got an injector hanging open on these cold mornings so I keep it plugged in until I can get a set for it. Their easy to replace but they are expensive for being identical to 7.3 Injectors.

basically what it boils down to is bigger truck, bigger money, bigger problems.

If it were me and starting out needing a good reliable work truck, take the 7.3, all day, every day.

If your fairly established and looking for a bigger truck with a bit higher gvwr for legality reasons, then take the 3126.
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