For sure the 7.3 liter diesel. Personally I think the v10 is the worst engine ford manufactured. The deisel engine will allow for more torque and if you are in a tough situation it could be run on alternative fuel sources.

 

Chances are you've never owned a 6.8 V10. Check this site alone. There are far more accolades for the V10 than people who claim they are "the worst".

 

Crawl ration is the highest gearing, 1st gear in 4low.

I haven't looked into the number on super duties, however when I had my Tacoma the auto guys had a ration of 80:1 vs 40:1 on the manual.

Guys with dual transfer cases were able to get to 400:1.

100:1 is pretty respectable in the Crawling world.

 

I was refering to rear end ratio.....4.30, 4.1, 3.X, etc

 

I was actually answering a question the OP posted on the first page.

Rear end ratio is only part of the story as it pertains to legitimate Crawling.

With this kind of weight, combined with the weight of the truck itself, I could argue would require dual 4:1 transfer cases.

With a double T case setup you could use any engine, either engine would supply ample torque to easily snap D60 or Sterling 10.5 axles.

The key to Crawling, is going slow, slower the better. You can't go slow enough. Way more control when going slow.

Check out pirate4x4 if you want to legitimately build a Utilitarian Crawler

 

For your intended use ill go with the v10, the 7.3 is good for highway and long runs (towing, hauling etc)
Dont worry about the horsepower it doesn't matter in low speed crawling situations what you need is torque, and believe me a 7.3 p stroke has a turbo that has to spool something to consider.

As for trannys you will like the auto way more than a hand shaker. The only thing I'll recomend is a hd transcooler with an electric fan since the truck will most likely be going up grades and stuff at real slow pace and the tranny will pver heat.

 

Ben you are in the minority with that statement care to elaborate on your reasoning without causing another 7.3 vs v10 fight.

 

The V10 is an alright motor, it just has a drinking problem.

 

Saying the V10 is the worst motor is just laughable. Seeing as Ford still offers it in the medium and heavy duty (450-750), real truck, segment I think Ford feels quite different.

Snowseeker is correct in that it has a drinking problem. But for the traditionally higher purchase price of a diesel you could likely purchase a lot of fuel before you reach that cost. Especially in a low mileage situation. The biggest downside is the smaller fuel tanks. That would be an upgrade to do, if there are larger tanks to purchase.

 

It seems like the consensus is that the v10 would be a good choice for my application, but the 7.3 would also work well.

One point that should be made (hopefully without opening up a can of worms) is that all of the posts saying horsepower does no matter, or the v10 has low end torque, simply is not true.

Horsepower is everything. Torque is simply a factor of HP, HP=RPM x Torque / 5252. Yes low end torque is needed for pulling/hauling/crawling but the more torque at a given rpm the more HP you have. Another way of saying that is the more HP your engine has, the more torque you have available at a given rpm when translated by the transmission.

Torque at the crankshaft does not matter as much as torque at the wheel which is provided by the transmission. The v10 3 valve has 365 hp @ 4750 rpm and 457 ft/lb @ 3250 rpm, the 7,3 diesel has 275 hp @ 2700 rpm and 525 ft/lb @ 1600 rpm. Even though the 7.3 has higher native torque (torque at the crank) the v10 has higher overall torque because its higher HP can be translated into higher torque at slower wheel rpm via the transmission. However, it does that at the cost of a much higher crank rpm.

Obviously the diesel's higher native low end torque is better, it has a narrower power band (more immediate available torque) and puts less of a load on the tranny. This is why the diesel is the choice for work horse hualing and towing. So, my original question was, since the v10 has to rev higher to get the torque and therefore does not have the immediately available torque would that be an issue hauling a load up a hill. All things being equal the diesel is better for that application, but it sounds like it is not a big deal, and the v10 can handle it ok.

Anyway, at this point I have decided on two options, the 2005 or later v10 3v with the 5 sp auto tranny, or the 2001-03 7.3 diesel with the 6-speed manual.

It is interested to note that Ford's specs on the 7.3 state that it has 275 HP with a manual tranny and yet only 250 HP with the auto tranny. I assume this is because of the frictional losses created by the torque converter with the auto tranny.

 

You're understanding the concepts, but not the practical application. Peak torque at 4,750 does NOT mean it's 0 everywhere else. Which RPMs do you think you'll be crawling at?

Nope, it's a different engine calibration. Power output figures are at the crank, not the wheel or transmission output shaft. The engine tune used in manual transmission trucks gives more power to the transmission. Presumably this is for transmission longevity; transmission cooling on a stock 7.3L truck is lacking.

 

I have a ZF6 in my 95 7.3 and with 4.10's, the transfer case in low and the trans in low it barely moves and is great for controlling the truck on hills. However given your intended use an auto would be better. The parking brake in the superduty isn't great especially with a heavy load. If you are planning on a using a PTO pump or anything else engine powered you won't be able to leave the trans in gear when parked. With an auto you can leave it in park to help the parking brake with the added benefit of locking all 4 wheels.

For low end torque which is what you want for crawling, the 7.3 is the better choice. Diesel is also a lot safer around the environment you will be in than gas.

One thing to add to your list regardless of engine is a locker for the rear, the factory limited slip won't help and the last thing you want is to get stuck.