I'm sure that this has been hashed out before, but I tried searching and didn't find anything. If you have a link to a valid thread, please post it. Otherwise, I'm here to ask what you guys think about the 6.2 vs 6.5. Let me give you a little background into why I'm asking. I need to pull the engine in my '99 CCLB to investigate the sudden low oil pressure (and metal in the oil). It's not the original engine in the truck so it might be a newer Navistar cast, oil cooled 506 or an older block rebuilt by some less-than-respectable company. I'm hoping for the 'good' squiter, but my luck says not. If it proves to be something less desirable I will probably start over from scratch on the build. I have been looking for a 2001+ block, but have had trouble finding a used one. I was reading about Heath's LSR truck and noticed that he used a 6.2 as the foundation because he likes some of the design features better. Should I go the same route? If so, what are the better casting numbers to look for? What ones should I avoid? Never owned any 6.2's so I don't really know where to begin. Also, if I go with a 6.2, how do you guys feel about having my machinist put the piston oil cooling holes in the block? I want POC, but I realize that lots of people get by just fine without it, and just as many hate it all together. Last question. Is there any credence to the idea that the 6.2 might get slightly better fuel economy? I'm trying to tell myself that it might, just as a way to justify using a 6.2. OK, let's hear it.