The most important part of painting is the prep work. You will need to get in and get the engine cleaned down to either raw metal, or solid paint, if you expect the next coats to stick. That usually means degreasing, rinsing thoroughly, that sometimes wire brushing or chipping any scale and rust. Following by rinsing again.
Then primer and "engine paint" aka high temperature enamel paint. Follow the can directions for recoat time, temperature, and correct primer, and it will last very nicely.
NEVER paint rubber hoses or belts. Even though Westerbleak does that, every maker of rubber parts tells you not to do so, the paint will cause the rubber to dry out and crack prematurely. (The same applies to wiring harnesses and wires, etc.) That's a sign of a poor workman.
Also never paint the alternator, since paint may stop heat transfer and cause it to overheat. If there are identifying plates or engravings, you might also want to mask those off or make sure they are not obliterated by the new paint job.
You can probably call the Krylon or Rustoleum folks (both have toll-free numbers) and ask them about the job, their tech support is great and sometimes the best products are not the ones commonly found on the shelf. Duplicolor makes engine paints also, they are sold mainly in automotive suppliers.