You guys can talk grade 8, double nut, ksi, psi, tensile strength etc all you want but, at the end of the day, most low profile Warn winches are held on with (4) 3/8" grade 5 bolts fastened to a cast, white metal type material.
Has anyone ever seen a winch pulled off the plate? I'm sure there are a few cases of the winch body breaking but I bet those failures are due to a home-made mounting plate that is not designed to prevent flexing of the plate.
disclaimer: the ksi, psi, and any other si is over my head.
Vince