What to use on firewall???

[Ricoh]

I spent most of my day Sunday stripping ( chipping and scraping) down my firewall. The previous owner coated it with what looks like stone guard or something and did a crap job of it. It was a lot of work with a sharp wood chisel but I managed to get it pretty well down to metal. I will sand it down and finish it up hopefully this weekend. What primer should I use and what paint would be best suited to redo the firewall???

Rick