Cab- Good point. At the initial start up, the oil pressure was exactly as it should be- quick jump to 60 psi at idle cold, dropping off to 50 psi at idle hot, with the brief delay at shut-off before it falls to 0. After a few passes, I noticed, but it didn't fully register with me, that the oil pressure was swinging quite dramatically when I was trying to sort out the carb/idle issue. The pressure would drop to almost zero whenever the motor fell off the idle. When that sunk in, the internals had already been externalized. My first thought was that a rod bolt had let go. The rod bolt that did fail was collateral damage. The cylinder wall crack was the biggie. I'll try and post a pic of the top of the piston. It was definitely hydrauliced, with absolutely no indications that piston and head made contact. I do have this to add- When I put the roller in, the cam that was shipped to me was for a Magnum, and had no rocker oil grooves. That was treated as no biggie, as I have friends with lathes. However, there was a small discrepancy between groove sizes, and the passenger side rockers have had a bit of an oiling issue. When I had the motor apart this time, I had my friend cut that one groove .010" deeper and about .015" wider. I no longer have a passenger side rocker oiling problem (cue the "Well duh, of course it ain't NOW" comments) I have a hard time believing that modest change up would have resulted in the bearing damage I'm seeing. 'Tis a mystery, wot?