I tore the motor apart tonight. The only problem piston was the one that was shown, all others looked great. All the rod bearings look great too. The mains showed some wear, but not sure of the cause. The #6 cylinder was really clean, no carbon on the piston or head. What caused this? I have a couple pictures of the piston, head and main bearings.

6773364-Cylinderhead.jpg (53 downloads)