I used Rustoleum Semi-gloss black on my chassis, after it had been sandblasted and primered with epoxy. Most of it is in good shape a few years later, but I must have had some light spots, as I saw an area of light rust when working underneath late this summer. I buy it in quart cans for about the same cost as one 12 oz rattle can and use my spray gun. POR-15 is about 4 times as expensive and not worth the cost, IMO. For what it's worth. GM didn't paint frames, and they generally lasted the 70+ years without serious damage.
Last edited by klhansen; 11/12/2024 6:49 PM. Reason: cleanup