What size and year of motor? If its a 71 340 I can give you a krylon paint code thats a dead match.

High Performance Mopar had an article on on painting engine with a gun. The key was using the right amount of paint 2.5 mils to be exact.They used PPG's Delstar with no primer. They cleaned and cleaned and cleaned it before painting using PPG 220 degreaser first then PPG 330 cleaner. Its the March 95 issue.