Over the years I have had too much experience with CAT engines. Just a couple points. It was already stated out that a CAT engine will not fit. Further, to spend a fortune on some modified CAT engine would be NUTZ. Consider the fact that should some knowledgeable "GREEN AIR" inspector stop you, you are out of business.

Also, as stated above, if your business plan is that you run 100,000 miles a year, you should plan on a new vehicle after 200,000 miles and absolutely before 300,000 miles.

And finally, buying a used truck to start just doesn't make sense to me, IMHO...

 

6.0's don't like to tow. If the 6.0 is out, and the Cummins is not an option, Why not consider a Duramax swap? It's the only other practical light duty diesel besides Cummins and Navistar that will easily fit size wise.

 

What? The 6.0L is at it's best when towing. Using it as a short trip daily driver is what brings out the weakness of the engine.

Also, for your information the 6.0L is a Navistar engine.

 

The problem about that little misconception, I believe anyway, stems from the fact that the 6.0 likes to be at operating temperature before it gets to working really hard. A lot of people just want to "blow and go" and don't want to drive it easy for the ~15 minutes to get it warmed up.

Once it gets up to operating temp, it's a hoss. My tows ~16k wonderfully.

 

In the past Ol hotrod bought a converted '75 Chev c.cab dually that had a normally aspirated 1160 Cat V8 coupled to a Allison 540 tranny installed. Thing was a stump puller. Pulled my 15K, 40', 3 axle Chap trailer over the 'ridge route', and Cajon Pass easily. Only problem was the 'old faithfull geyser' syndrome, i.e. steam out the radiator cap, etc. Why? The conversion did not have a vertical flow radiator. The Chev cross flow would not let the bubbles out of the water per the local Cat dealer. Before I got around to changing the radiator setup, the truck got "T-Boned". I took the insurance money and bought my first of three F350 C.Cab Duallys and haven't looked back.

Most do not think a conversion all the way through. Front springs, are there heavier spec'd ones avail. Added steering weight and turning torque; is there a power steering pump on the new motor. Starter motor location; how will it fit in the chassis. Chassis; more torque equals more twist, etc. Longer 6 cyl motor in place of a V8 - 4 cyl length and radiator clearance, plus a new shroud req'd.

Most sensible in my 78 yr old mind is get a mid sized Ford F600 / GMC / International diesel powered rig. Plenty of Braking Power, GVW capacity, and that's just for openers.

Lastly, incorporate and get your own thing going. Subchapter S with mother, brother, sister, wife,?, (problems later,?) or someone, to "have it your way..." And get financial advisor/book keeper so you know where you are making, or losing money, at in YOUR business.

 

Get a Chevy Duramax if you've had bad luck with Ford and Dodge, reliable strong trucks.

 

I'd just throw an ISB in there and call it a day.

 

Hopefully 11 years later the OP fixed the 6.0 problem.