My dad and I just did this conversion this past weekend.
We used a 1967 Dual master cylinder and the pushrod that came with the Dual MC. We were so frustrated for about an hour because we couldn't figure out why there was no pressure building up (pedal to the floor).
Just as we were about to pull out the new MC, we compared the new pushrod to the old pushrod. The older one was about 1 inch longer. We bolted that old pushrod in BINGO! Pedal was instantly back to normal.
NOTE: use original pushrod!
Also, regarding the lines. We disconnected the rear brake line from the distribution block, bolted a female to female adapter to the rear line, bent a new line to fit from there to the front of the MC.
Plugged the open hole in the distribution block, ran a new line from the rear of the MC to the distribution block.
NOTE: front lines go to the rear of the MC. Rear brake lines go to the front of the MC.
Question for experienced brake mechanics:
You guys mentioned previously to NOT use COPPER lines. Why?
Also, we bought straight steel lines (with fittings already attached) and the fittings were in a gold like color. Those weren't copper fittings were it? No leaks so far.
Sorry to add those questions to your post. But if someone answers it, at least you'll have a better knowledge.