Painting Engine

The reason the factory did not use primer on the engines is that it adds to the cost.

Another consideration is that the thicker the paint (and primer) the more the engine will retain heat.

As for painting the engine, it's like any other metal surface. Make sure it's free of rust, dust, and oil. If you want color to adhere to the soft metal parts (e.g. valve covers, air cleaner housing, coil bracket, timing cover) give a shout to Cudachick1968 about powder coating. It's more expensive than paint, but much more resistant to scratching. Leanna does great work and gives a discount to FABO members.