Loctite SF7900 under any wrap does wonders
I sand blast and coat all my headers with it, even if they aren't wrapped, with those I just hit them with an exhaust paint over top because when you get it thick it likes to flake if you smack it
It's a lot cheaper than buying them ceramic coated, and good luck finding ceramic coated manifolds for these trucks
Edit: just an FYI, I don't use an oven for any coating cure on exhaust, I bolt it on uncured, idle 10, let cool, idle 20, let cool, and go for a half hour drive