The Ford 7.3 Power Stroke is a light truck version of the International T444E. There are some things between the two that are different, many of them are cost related issues to keep the price of the engine down for Ford customers. The waterpump is one example.

The cooling system on the 7.3 Power Stroke is way over kill. Additionally, the ECM does not use the coolant temperature in making adjustments to fuel timing, ratios, etc. All of that is done by using oil temperatures.

When the 7.3 Power Stroke was introduced in 1994.5 through somewhere in '95/'96, Ford used and inventoried thermostats that were 203 degrees, the same that International used in the T444E. The EPA intervened and found that the light duty Ford motor produced too many NO2 emissions. Ford replaced its inventory with a 195 degree thermostat. They are not interchangeable between the T444E, which is a medium duty application, and the 7.3 Power Stroke because of the difference in the water pumps. There are some places that are making 203 degree thermostats for 7.3's. It raises the oil temperature, and I found that doing that improved my FE about a 1/2 to 3/4 MPG. Additionally, throttle response was better, and the engine was smoother in the 1800 to 2000 RPM's when the 7.3's kind of drone a bit.

More information here...
https://www.dieselsite.com/index.asp?...ROD&ProdID=186

30MPG? I think you'd have to work hard to get it. Generally, often, the problem with a diesel is that it has so much umph, they get to be too fun to drive; it's a rush.

I can get 30+ on the highway but I have a 2.8L CRD in a 4300# vehicle. Before the Lift and bigger tires I had hit 33+ a couple of times. I have the MAF defeated but on the Liberty it is a "single loop" sensor, so it does not affect anything else. Just bloked off some more of my grill today...hope it helps...

Off topic, but 3-5mpg with a 454? We got 8 highway in a loaded-down '87 Dolphin 34.5' motorhome with a 454 on the highway. Never ran enough in-town miles, of course, to see what that was but accelerating 10.000lbs it must not have been good. If yours is getting that low mileage in a pickemup, I'd say there's something wrong with it.

As to the diesels, trucks here don't get much better than gassers unloaded, but are built to haul. Under load they outperform gassers in fuel economy quite significantly. Diesel tuners and a good 4" or 5" exhaust can really help them out, too.

F-350 made with Cummins 4-cylinder diesel
 

In Brazil the Ford F-350 is available with a Cummins 4BT 3.9 litre tubodiesel. See: https://www.fordcaminhoes.com.br/caminhoesnew/#F350

That would probably get better fuel economy than any full size pickup sold in the US. I once drove a medium duty cabover truck with this engine and it was very rough running and noisy but probably not as bad if it is mounted in front of the cab on a pickup.

That F350 seems like it's pretty light compared to an F350 in the domestic market. Still interesting. Probably a licensing issue with Cummins in USA.

The Cummins B3.9 engine is also sold in Brazil in the dual rear wheel F-4000 which looks like a US F-450. See: https://www.fordcaminhoes.com.br/caminhoesnew/#F4000

I don't know Portugese but just looking at the numbers in the specs it appears the GVW is 6800 kg on GVCW 10,400 kg. Multiply by 2.2 to get pounds.

I vote for a '94 to early '98 Dodge/Cummins. They had the 12 valve head and consistantly gave better MPG than any of the other light truck diesels. The 7.3L power smoke comes in a close second.
A mild upgrade in injectors almost always adds MPG as well as power. Advancing the timing event adds MPG and power up to a point also.
Stick to the manual trannies. They will let you get your load moving with less effort.
Many claim that a better flowing intake and exhaust will help MPG. I think that until you bring power levels up quite a bit it has no affect.

Another claim of Cummins MPG superiority. I hear them a lot but when I throw down the gauntlet for a a MPG roadtrip to separate the truth from the BS...crickets. All the Cummins boosters shut up and run.

Yeah I know about the guys in Diesel Power with the 30 MPG Dodge Cummins. All the grille blocking etc was window dressing. They got 30 MPG by driving 40 MPH.

I'll see that and raise them one. If I can just idle down the road (yes I can go down the road at 650 RPM) I'd probably scare 50 MPG.

There is other one valid condition for MPG testing. The legal limit at max gross.

I'd have to agree. I've driven the 95, 99,00,01 psd. I've driven the 89-91 ford IDI. I've driven the 91-93 dodge 12 valve and a 96. Bottom line, the 99 PSD got the best mileage of all of them. The 95 psd got a one time tank at 23.5mpg , driven at 62mph on the highway. I think all of them were capable of near the same mileage given good conditions. My favorite of the bunch was my 91 dodge automatic. It was very simple to mod and tune.

Cummins engines - particular the 12-valve - are great fovorites for hot-rodding becuase that lawn-sprikler injection system can easily be made to pass enough fuel for lots of HP. That and they are very compact and easy on the mechanic.

As for being more efficient - t'ain't so.