the cast of the block makes the paint hang on i have been painting engines with two part paints for 28 years it will not fall off or burn off less is a head with ports off the head like a pontiac not lot of prep needs to be done but i ways did long as the parts are clean clean clean the paint will stick would not clear the engine but thats up to you i used the delstar . dau 75 clear for alum intake s . concept paint to. for a time i was on the military kick and shot the hole engine alum intake and all with DP 90