Swapping front drums to Kelsey Hayes

That's weird. I took a Kelsey Hayes disc brake setup off my 72 Demon and installed it in my 71 Scamp. Changed the master cylinder as it was drum / drum to a 73 Duster power master without the vacuum assist, took the proportioning valve and the calipers from the 72 and hooked up the lines. This is non power brakes if it makes a difference. But I definitely have no secondary block. I did however change the rear wheel cylinder size to make it easier to push the pedal.
Reading that link Mattax gave, I did see where that larger cars got a secondary valve to control lock up in icy or wet conditions, but I believe it was only the larger ones.
Mind you this is later and I didn't read the 67-04 link. Maybe being 69 makes a difference?