"FYI"
Your friends are wrong on several points. First, the engine you are referring to is a inline 6 not a V6, a big difference. Second, Cummins builds many engines all the way up to a 120 liter diesel. Some are used in locomotives, oil drilling rigs, power generators, various construction and mining applications to name a few. They have V12s and V16s, some are rated to 4,000 horsepower. And as far as a V8 diesel, I do not know if they build it anymore, but they did have a V8 that was called a 903 and was used in the trucking industry. Note, it did not do a very good job and I have not seen one in many years. You could tell what it was by the distinct sound it made.