Before you start painting, you need to wash the block really well on the stand.

That set of heads (pictured) now on my engine was painted by the machine shop, but if they don't do it, I never do. If you want to paint yours, use hi-temp paint and just mask off the areas you don't want sprayed and don't load it up around the spark plug holes.

The block can be sprayed with any engine enamel. I don't mask anything, but rotate the engine on the stand and try to angle the spray so the decks and pan gasket surface don't get too much overspray. You'll need several coats of paint for the block and it will get into places where you don't want paint - but if you don't wait too long, a towel and acetone will remove it fairly easily with a bit of rubbing. After the paint dries, you'll want to chase every block hole with a tap.

Hi-temp brake caliper spray works well on brackets and the lower intake if you find the color you want. Exhaust manifolds need the really hi-temp paint, which will last for a while, but eventually burn off.

There are some specialty paints that will work better/last longer than anything I use, but I haven't tried them.

Frank