Drum-drum dual masters: Ford passenger cars 1967/

Most of the dual Ford master cylinders are about the same length, the boosters are not.

F100's from 1968 had dual master cylinder drum-drum brakes into the early 1980's. Many of the F250/350's from 1968 had drum-drum dual masters till 1973. Discs were first offered as an option in 1968 on F250/350's, but prolly only 25% came with discs, most were drum.