Use the plasticote paint out of a spray bomb as said but the trick is to have a lit butane torch going while you paint, heat up the engine just a bit and then flow the paint from the spray can, going back over it as it lays on the engine.. I painted mine in 1994 and drive her like a raped ape and the engine looks as new.. every now and then you spray a bit in a container and use a paint brush to touch up on the center part of the heads because of the heat discoloration and on the intake.. if you want to see check out on
www.ultimategto.com and search out engines in Orbit Orange Judges. I have a couple in there Good luck
Pete