With all due respect, you don't know this particular 6.4 or how it has been taken care of. It has always been reliable for me in the 13 years I've owned it and should be going forward if it is taken care of. Apparently you feel pretty strongly about this to be putting this on my post, but I don't think it's appropriate.

I ran a 6.4 daily for 2.5 years pulling a cargo trailer and load averaging 7K. The only things it needed were filters and 1 set of batteries. I put 125K on it in that time frame. I deleted it the day it hit 100K and ran an XRT Pro on the hottest tune. I picked up 4 mpg on that tune.

The problem with the 6.4 is people tried to run them like a race truck and push way too much boost, which would lift the heads. I did see 55psi one time and it scared the crap out of me.

The other problem is letting it sit. That motor needs to be worked on a regular basis, but not beat on. The guy that bought mine rarely drives it, and has issues like water in the fuel, dead batteries, etc.

If I needed this, I'd buy it in a heart beat.