Painted a block (external surface only) using the recommended primer with that system of engine paint. About 3 months later the topcoat of paint started flaking off. I could remove most of the paint with an air blower. The primer stayed with no flaking at all. I was told it was because I didn't run the engine and get the paint warm right after application.
Just think if that flaking had been on the inside of an engine. I know there are some who will disagree, but I have never even considered painting the inside of a block for that reason.
