I called around trying to find parts to use the Toyota brake backing plates, cable and lever. The few salvage yards that had 71 to 85 Toyota Celica's told me they were setting flat on the ground and if I wanted to look, I would have to raise them up, then they would tell me how much they wanted for the parts. Didn't sound like a good idea to me so I started searching.
Electric Line Locks used in Drag Racing wouldn't work because they are electric and draw a lot of power
I'm going to use a Drift Brake like the guys use for sliding the rear end around curves. Drifting seems a bit insane to me but then I'm an Old Man. But, the lever and master cylinder assemblies are available on e-bay for $34 to $190 Being a tightwad, I chose a $43 one with a reservoir. That way I wont have to depend on fluid from the car master cylinder. I don't know that it will work but we'll see.