This is a motor I bought a few years ago and it has been sitting in my garage ever since. It has less than 100 miles on it according to the builder. I was getting ready to sell it and was giving it an inspection, and found that 6 of the exhaust valve guides have a shiny copper build up on them. The intake side is absolutely pristine. I've never seen rust like this before, and I know my pictures aren't much help, but has anyone encountered anything like this?

 

Just looks like some rust on the cast iron guides, nothing to worry about. It is normal for an engine that has been sitting.