Dunno about you, but I like restoration tasks that only have to be performed once, then, never have to be done again. So what to do about rusty exhaust manifolds that rust, burn, and peal? The Eastwood Company has High Temp Coating for hot exhaust manifolds you can apply in a matter of 30 minutes once manifolds or pipes have been media blasted and are clean. Apply Factory Gray High Temp Coating with a paint brush. No special equipment is required and you won't have to spend much to make it happen. If you drive your Mustang daily, count on having to strip and apply High Temp Coating eventually. Occasional drivers can last years. Go see www.eastwoodco.com for more information.
There's also Jet Hot Coatings, which offers two kinds of gray iron high temp colors for classic iron manifolds and other hot surfaces. Jet Hot offers a variety of colors and temperatures, providing a high temperature coating that not only seals out rust, but seals in heat. See www.jet-hot.com for more detailed information and prices.