They were used in '67-'69 340, 383 cars. They had that metal guard, a stronger spring I think, a pin is used to attach the spring to the bracket, and they had bearings instead of plastic bushings.
I got mine out of a 73 340 duster in the junkyard, and they have the bracket, and needle bearings in them factory. They also have the twisted brake pedal, so I'm sure they are original to the car I got them from.
