If the pitting is indeed just cosmetic sand blast the frame and fill the pits with any good body filler. Sand smooth and prime. Paint the frame with any good chassis black, Rust-O-leum, or Por-15 type paint. If the pitting turns out to be holes and strucural weakening the services of a competant welder should be used to cut and weld in new steel...............Bob
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Bob Beck
39 Chev PU
69 big block Corvette
55 Buick 66C
57 Buick 46C
55 Olds S-88
56 Chrysler St. Regis
AACA, BCA, WPC, USHGA