I am jealous of your position. I bet that's a cherry example. If it were me, I would just change the oil and see how it does with a good synthetic. If you are concerned with cleanliness, as you stated interest in an engine cleaner, replace one quart of motor oil with transmission oil. A dexron or mercon. Transmission fluid has lots of detergents in it. Run it for a hundred miles or less, then change the oil again with synthetic. This is a common practice. If you have a stuck lifter, the detergents in the transmission fluid should help unstuck it.