Mopar Performance Street Hemi Orange.
Clean/prep the motor well, I use brake cleaner. Let it dry. Srpay it off with compressed air.
No primer, just spray it on, light coats to start.
Never,ever,have had any kind of issue with this paint.
This works for me too. Right out of the can on several engines I have done. Clean, Clean & Clean first. I also use heat to warm the parts up and chase out any moisture.
Now if you really want to go hard core. There are shops that high temp powder coat now. The entire engine. Also motorcycle engines that run hotter than a car engine. I have done snowmobile engines in the past and they look great and last but, it cost way more than a rattle can. There are a million colors to pick and you have to grind it off. I'm going to use Plati Coat clear engine paint over the Mopar 1587933 and a very lite scuffing. I want a high gloss look. I'll put in more pics as I go. Cheers