I think the easiest swap to do would be to put a Cummins in it but would still be expensive to have someone do unless u do it yourself so then u just have to get and fabricate parts. That being said, Why would u want to get rid of the V10? i've seen them run up to 300K without issues and their pretty fast...Your call though
Well if this guy is pulling regularly then a diesel would be worth it. You wont see the fuel milage loss with a diesel like you would with that gas hog when pulling a load. My dad has a V10 and pulls a 5k lb box trailer and gets like 5mpg. I pull my 10k lb 5th wheel and get 9mpg at 75mph.
Cummins would deffinately be a great swap. But I just read something today that I really didnt believe..."Why did International choose to build a V-8?
When designing the first diesel engine for Ford trucks, International wanted an engine that would make the truck versatile, as both a work horse and reliable daily driven vehicle. After all, it was unlikely that a trailer would be permanently hitched to all these trucks and towing be their sole purpose. Therefore, a V-8 configuration was chosen. The prefered V-8 gave the trucks plenty of low RPM torque for towing, and built horsepower throughout the RPM range for better daily driver performance. In comparison, an inline 6 cylinder diesel would peak out at a low RPM and lower performance in the high RPM range, hardly desirable for such a versatile pickup. The V-8 has proven to be the most popular design in a light duty diesel truck."...got it off internationalpowerstroke.com .
I guess the biggest thing for me to believe about this is that I've heard of cummins pulling bigger loads uphill and walking off and leaving a powerstroke. But I guess that just depends on the mods.