Used
HERCULINER on under cab and underside of fenders also. Was very happy with the
RESULTS I would not use it on the frame.
I used Eastwoods rattle can frame paint. But if I had to do it over I would just use rustolium satin black sprayed with my cheap harbor freight purple hplv gun. I've had good results with spraying thinned rustolium on the inner fenders and rad support.
The Eastwood extreme chassis black rattle can paint I used was expensive, took forever to dry, and overspray can be a big problem.
I don't live in an area where rust is a problem
Good luck
