Sandblast the frame and use POR-15 the same day, you'll spend $30 for a quart and maybe use a quarter of it on your frame. Keep it covered or indoors until you can get the body on it and people will think you had it powdercoated.

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1965 Chevy C-10 Gallery page
My Chevy truck pages more info and pictures!
1961 Studebaker Hawk
1962 Shasta 16' AirFlyte Travel Trailer
1941 Case Model S tractor