Alot of people have had good luck with por-15 engine paints. Do a search, Txfirefighter had a engine painted chevy orange and it looked great. They have engine kits that comes with everything you need to paint your engine.
Never tried painting my exhaust manifolds but eastwood has some paint for manifolds. Haven't used it personally but have been happy with Eastwoods stuff in the past.
http://www.eastwood.com/shopping/pro...iProductID=733