67 dart front disc upgrade made..still not right

Get a shop manual, anywhere from 67--72 and read it

You can download a 66 and 70 manual from MyMopar

http://www.mymopar.com/index.php?pid=31

link

http://www.mymopar.com/downloads/servicemanuals/1970_Plymouth_Service_Manual.zip

You can download some manuals from a thread here, but some of the links are broken. Unfortunately, I think the 72 manual link is broken now as well PM AbodyJoe and see if you can get it. Some of the earlier links posted that are broken were reposted later

http://www.forabodiesonly.com/mopar/showthread.php?t=132309&highlight=manual%2C+download

Drum brake cars DO NOT HAVE a metering valve or prop valve. All they have is a combo distribution block, which also contains the piston operated warning switch. It might be possible that thing is all gummed up inside, has shuttled off to one side, and is plugging one port

You probably need to buy some fittings and a hi pressure gauge so you can check line pressures.

A "rock hard" pedal with a booster CAN mean a bad booster. Make absolutely sure the pushrod/ cylinder have enough room to return properly