[Special K]

My personal favorite is POR 15. I've used it all over the bottom of my '73, the stuff is tough as nails. It isn't cheap, but a little goes a very long way. I coated both rear swing arms, axles, brake covers, stub axles and every single nut and bolt associated, with less than 1/2 pint (brush applied). Just make sure the parts are prep'ed right before you slather it on.

'73 2.0L (Oh the glee to be "rust free"!)