My $.02
Do you know what paint line you are going to be shooting your truck with? I would recoomend using PPG DPLF series epoxy primer. Its an excellent corrosion resistant primer/sealer. It is non sandable, just a sealer. Then spray it with PPG K-36 primer. You can shoot just about any PPG topcoat over the K-36. The DPLF primer must be coated with something within a week of application for it to work properly.
Other paint lines may offer the exact same performance as what I've mentioned, I'm just familiar with PPG.
