You got it man. After the booster sometime in the next week or so, I will have 100% new 4 wheel drums. They still blow. A malfuntioning booster can cause burnt valves on cylinders 5 & 6, and contributes to a rough idle. Not to mention is a little dangerous since manual brakes are no fun. A rebuilt booster isn't too bad if "Booster" Dewey is legit, the ad I posted yesterday. $135 is not bad, compared to the $400 Specter wants after they recieve your core. Turned out that the biggest problem with my brakes was the master cylinder, not the wheel cylinders as suspected. You know that if you are doing a disc conversion you should go ahead and get a master from a disc year, so you don't have to remove this valve thingy from the front circuit of a drum year master. When I do a disk conversion I will try to use the tandem booster that's on 78's and some other years I believe, a friend has a stock 78 and his cruiser stops better than any other car I've ever driven, compared to mine, the worst I've ever driven.
The little valve thingy seriosly takes only 5 minutes to remove. Just dont forget to do it before you bleed the system out or you will be re bleeing it. Be sure to remove the hard line from th plug at the master cyl before you try to remove it or you will not be able to get a socket on at least or you could twist the line off if you're using a box end.