I went to the pick n pull today and got some parts off a wrecked 1978-1980 Malibu that I saw on a previous trip. It had what looked like a factory manual brake set up so I grabbed the master cylinder and block off plate. The block off plate was a thin 2 piece sheet metal covering, and inside the car it was the skinny pedal from what would have been a manual car, but it was a column shift auto tranny. Does that all sound correct that it is an original block off plate? Unlike the booster that has studs in the booster and then the nuts are in the passenger compartment, this had the studs in the firewall and nuts were in the engine bay. I wacked the studs quickly to see if they would come out and if there was another support plate on the inside of the firewall, but they were pretty stuck. I would have thought that the firewall would have been a little thin to support pressing studs through.