Having let the project slip for a few years, I picked up on the engine to start the process of preparing it for paint. A lot of people had warned me that I needed to check all the oil passageways for the ingress of vapour blasting media.
This is a very fine sand like substance and because of the high pressures used in vapour blasting, it gets into all the small oil passageways in the head, and other parts of the engine that were blasted.
I bought one of those cheap iPhone endoscopes and I was horrified at what I saw.
ANY amount of this stuff in your oil and goodness only knows how any of the bearings would have survived.