Suggestions for underbody coating

[StretchEMF]

Hey all, I am looking to coat the underside of the Jimmy to help prevent rust. My dad used to always just use spray paint. Is there something better than just spray paint out there?

 

[Rottenk10]

I've used por15 on my frames before worked out pretty good , also bed liner on the underside of the body

 

[meanboyjr]

3M Body Schutz.