ClassicCar

I'd say if you're doing a "frame off" the best way to go is to have it powder coated.

Depends on whether you want to restore it to original or over-restore it to what it never was to start with. Originally chassis were painted with a product called, logically, "chassis black", a semi-gloss oil based paint that stuck without primer, and was reasonably resistant to stone chips, etc. Not particularly flashy, but serviceable. If you want something more glossy, use ordinary spraying enamel, or really shiny and hard, then go to two-pot epoxy paint. Powder coating, I steer away from. I have worked on a '27 Hudson chassis that was powder coated, and it was just too difficult to remove from threads, holes and to scrape off to get a decent ground anywhere. My two-bob's worth.
Geoff

Eastwood make a couple of nice chassis paints. A durable satin black and a new ceramic paint that is pretty darn durable. I just test painted a Hudson front end I had cut from a car to test it. I have beat on it and it does not chip or mark easily so perfect for resto jobs. Here is link to stuff. http://www.eastwood.com/2k-ceramic-chassis-black-satin-quart.html