master cyl. for pwr.disc brakes

Jerry I don't have a Demon but the M/C I used on my Cuda conversion to disc brakes was for a 73 Dart and NAPA showed the same part for both power and non power brakes and I think the M/C's were the same for most A body cars. You can go to www.napaonline.com and do a search for your self to see what comes up. They even have pictures there. Just to let you know I ran into problems with getting a good rebuilt M/C and several other guys on here posted the same problem. Some other guys also posted having problems getting different looking M/C's by the same part number. I finally went with a new one from NAPA. Only cost about $15 more too.