Brake pedal swap from manual trans to auto trans

[1964c20]

Can anyone get me pointed in the right direction in regards to the brake pedal in my 1966 C10. My C10 was a 3 on the tree and I'm putting a 700R4 in it. I want to eliminate the clutch/brake pedals and put an automatic brake pedal in it. What works as a good swap for a 1966? I guess I could use the original brake pedal and remove the clutch pedal but I like the looks of the bigger pedal in the automatics. Any advice would be greatly appreciated!