It can be done... however, with that being said there are some things that come along with it...
First, cast items are the worst parts to coat... mainly because of the outgassing. Cast Aluminum and Cast Iron parts will outgas. The more oil and grime that has been around the particular piece and the porosity of the parts, the worse it will be.
Hot tanking will help.. but you are almost guaranteed to have some pin holes in the coating with normal powders.
There are some outgassing forgiving powders though.. just not in the rainbow of colors that normal powders come in.