My truck isn't here for me to look at right now, but I'm going to try to use the 4 wheel drum brake master cylinder off my '67 Camaro and a distribution block from my '66 Chevelle. The plumbing is very simple where the front line of the master goes to the distribution block and then branches out to the front brakes. The rear line from the master will go directly to the rear. I may be able to use the original distribution block and close off the port to the rear and keep the fronts on it and run a new hard line from the master to the rears. If the Camaro master doesn't have enough displacement to move enough fluid for all the wheel cylinders, I will look at a '68-69 C50/60 master, as they should have gone to the dual by then too.
