Heavy duty testing uses the "B" scale. B10 means 10% fail at a certain mileage, B50 means 50% fail, etc.
International T444E and Ford Powerstroke 7.3 have a B10 rating of 200,000 miles. B50 of 350,000 miles. That means half of them make it to 350,000 miles of hard use with no major repairs.
The Max-force Ford 6.4 liter - as Ford has a B10 rating of 262,500 miles. B50 - 375,000 miles.
Cummins. The 5.9 diesel has a B10 rating of 210-250,000 miles and a B50 of 350,000 miles. More or less the same as the Ford IH "Navigating the Stars" diesels.