Hi Don

 

For most of the cowling, it doesn't get all that hot but for the turbine and turbo guys, it can get a bit stuffy.  I'd suggest a high temperature paint like engine enamel over sandable epoxy primer.  If you don't have the high temps near there and want a showroom finish, epoxy prime and paint with LPU like what you're going to use on the outside.  I like Awlgrip from US Paint but the PPG stuff is great, too.

 

Dan