I've had cases where the part number on the cam shaft was actually a casting number which didn't match anything in a parts book.

The right side cylinder bank is often the one that seems to weat out first with the cam shaft being the biggest problem.


Are you saying you replaced one piston and had that cylinder bored oversize? Not sure how well that works.
I think the cylinders are lapped in with some sort of special slicone paste. I don't think they're chrome plated but the piston rings sure could be.

You were lucky to get all of the inserts installed so the head bolts would fit. Some of them are drilled at a slight angle which is why you need the guide plate. Maybe that's how you did it?