Finally got the underside painted. Did two coats of R4 red. Fortunately I had the car painted in 1982 before I lost the fender tag so I knew what the correct color was. Completely wire wheeled the rear axle assembly. Did half of the backing plate before realizing I didn’t get a before picture. Had to use some needle point grinders with the dremel tool to get every bit of rust and crud off of them.