My 1966 Valiant Effort

A lot of beefing up of the frame rails and K-frame, but you will need a stiff structure for those new coil-over forces. For people keeping the T-bars, I don't think a little K-frame rust is a big deal since I doubt the UCA's take much load. They are just there to orient the wheel and bend up and down easily. My 64 & 65 had that whole top of the K-frame filled w/ undercoating and gunk, but the metal was solid underneath.

Re painting, several rust converters say to use only on rust and not on clean metal (fine print). For bare metal, an etching primer is best. Kind of hard since you usually have rust and bright together. One might use rust converter, then sand to bright and leave the converter in the pits, then an etch primer. I usually use Rust Destroyer, which claims it is the only paint that both converts rust and etches bare metal. Comes in quarts or spray. Home Depot carries the spray next to the Naval Jelly. Before that, I wire brush, scrape w/ file, sand blast, air blow, naval jelly, sandpaper, repeat. That is 80% of the work on my cars. Smarter might be to strip it all and take the shell to a media blast company, but I am more cheap than smart.