Distribution/Combination/Safety Switch Block

I need some clarification/opinions on the distribution/combination/safety switch block. I have a 1968 Dart with original power drum brakes. The car was swapped to B/E pin type discs and 11" rear drums, still with power booster.
According to the 1968 parts book, the brake distribution block(where all of the brake lines are attached with the safety switch) is the same for all drum brake cars and for cars with front disc brakes. If you had discs in 1968, there was also an inline "delay' valve plumbed in the rear brake line.
I'm still sorting out my brake issues and it has been recommended that I needed to change the distribution valve as my new discs are 2 pot instead of the 4 pot 1968 style and that there is more fluid needed for the 2 pot style.
I called Inline Tube and talked to Tech Support. They said that there is no difference in the distribution block from 1967-1974. If you had the earlier cars, you just added the "delay" valve in the rear line. For the later cars, the delay valve was mounted on a bracket with the distribution block(instead of plumbed separately). Supposedly they are "expert" in this.
OK, now I'm confused.
I'm open to thoughts/suggestions as well as vendor recommendations.
Author: admin