I went to look at the 6.1 today- talk about a bad deal. It was in the back of a mechanic's shop, with a bunch of other pull-out motors. First thing that caught my eye was a blown 6.1 piston/rod that was near the 6.1. The motor was quite clean, too clean. Upon closer inspection, the head gaskets had some sort of assembly lube on them, telling me they had just need put back on. When the owner arrived, I asked him what was wrong with it, and why they pulled it apart. He flat out lied and proceeded with a story that he couldn't keep straight. I walked away at this point.
Steer clear of a guy named Charlie with a 6.1 on Richmond in Houston!