I have a 1969 Chevelle Convertible that I recently started working on. I believe it originally did not have power brakes(many parts missing), but has disc's on front and drums rear. I have purchased a new distribution block that mounts to the frame to replace the old one. Do I also need a proportioning valve at the master cylinder? Or can I come directly out of the master cylinder into the distribution block? I am planning on installing a 7" dual diaphragm power booster.

if its a combo valve, that is all you'll need.