'03 Ford F-250 with V-10 gas engine

I have an 01. Check the exhaust manifold bolts. They are prone to snapping the heads off the bolts and can be a pain to replace. I replaced them myself after several broke off and I got an exhaust leak. If it has 2 valve heads which I think it does, like mine, there are only 4 threads holding the spark plugs in. Some folks have had the motor spit out the plugs messing up the threads. I replaced my plugs and it wasnt a huge deal to do. Just torqued them very carefully. Despite the exhaust manifold bolt PITA repair I am very happy with the power train. Like you I live on a farm.My excursion fills in alot doing chores. I gets around 10mpg pulling my TT or livestock trailer. Does alittle better hauling hay with the flatbed.
Not sure about the 35s and a TT. I am sure someone will answer that.

Check spark plugs, see when they were last changed. Can't tell you about longevity, but I know that is a very valued engine and will tow all day long (fuel tank permitting...).

Make sure the lift kit is high quality and that your payload and GVWR is not changed because of the kit. Other than that, you would just need to worry about buying a hitch with sufficient drop. My stock 2015 Ram is very tall and required me to purchase a 6" drop hitch in order to tow my trailer level.

Spark plugs should have been changed at 100k. Pricey if you have it done. Better job if Ford did it unless owner really knew what he was doing. My 410 towed better than my 373 differential did.

I own a 2000 2 valve V-10 and they run good but fuel economy is not a strong point. I would not personally want to tow with a lifted vehicle, seems like it would be unstable at higher speeds. Then again I tend to push my vehicle's limits.

Others have already spoke about the exhaust bolts and plug issue. I had a trusted mechanic change the plugs and coils. I bought mine a with 169k on it.

I would also make sure the tires are load range E for towing.

thats a lot of tire ,wonder if it was used heavy off road??

Me personally, I would opt for an 05 or later. Many problems fixed and more power.

I'll bet its been run hard. Fuel economy sucks!

I own two of these trucks - an '00 F-350 and an '03 F-350. The '00 is a crew truck, the '03 is my daily driver and trailer-hauler.

The '00 has 310K miles on it. It popped a spark plug at about 120K, owing to my ill-advised decision to let a lube and tune place replace the plugs. The repair ran about $600 and we've had no problems since.

And when I say no problems, I mean NO problems. Not a single repair. I finally had the serpentine belt replaced a few months back just because it seemed like something that should be done on a truck with 300K miles. Tires - fluids - brakes - batteries - wiper blades. Not bad for a truck that runs every day loaded to about 10K pounds, although it is starting to burn a quart of oil in about 2K miles.

My '03 has been slightly less reliable in that I had to replace the air conditioning compressor at 190K miles. It also has started using oil at the rate of 1 qt. per 2K miles. The drivers seat tore at about 200K miles and the compass has never worked right but that has been the extent of repairs. Mine also weighs in at about 10K pounds without the trailer which makes everything work harder.

Fuel economy is not the best - figure 10 MPG loaded, slightly less towing. A diesel might return better fuel economy but the repair bills will kill you.

My next truck will be a 2010 Ford - the last year to the V-10. Being as I wait for a truck to start costing me money it may be several years before I get one.

The lift may be an issue if you buy a really big trailer. If it is you can return it to stock height fairly simply.

I'd look at the tires and make sure they're "E" rated before you load the truck much. A lot of the off road tires aren't rated to carry much weight.

My V10 has been great!

I do the spark plugs, transmission fluid, and coolant every 100k miles. I preventatively did the coil packs and injectors at 375,000 miles, and last month did the timing chain at 410,000. Commercial-use V10s often need a timing chain around 500,000. Mine gets used especially hard, so I did it earlier than most. For recreational use, you probably won't ever need to replace it. I also did the A/C compressor at the same time because it was starting to make a slight growl. Oh, and the alternator was replaced around 395,000.