Although, even with all the issues with the 6.0L, you have to admit that it is a masterpiece of engineering architecture. Unfortunately, the rush to get it onto the market limited the testing that would have discovered most of the issues. Or so I have read. The 6.0L is the controversy that broke the relationship between IH and Ford.
The 6.4L however is the child of the severing ties between Ford and IH. As you could probably guess, Ford had a bigger hand in the construction this time and their many efforts to prove their hard work are WELL documented. Such as the loaded road test trip across the USA.
The newest addition to the diesel family, the 6.7L is truly a work that surpasses both engines in design and architecture. If you search around youtube, you will find that Ford really got their hands dirty this time around. Many brilliant innovations from what I saw. One big change for example that I noticed (engine wise) were the relocation of the exhaust manifolds to the TOP of the block, feeding directly into the dual turbocharger. Hell, even the turbocharger is an innovation...Dual compressor wheels within the same turbo cartridge. There are many more that I could fill up this page with, but I'll let you guys check it out for yourselves
I have to say I'm impressed with the work they have done and just maybe I'll get to drive one in the next decade...or two. Also, as far as working on the 6.0L up to current models...proceed with caution and be prepared to be on the computer often to look up information.
-Dave