[Richard Grant]

I would install a brake pressure guage on the front brakes. If you do you will love it when doing a burnout. You can pump the brakes to a set level each time. I usually set mine at 900 for my burnout.
You are running factory steel lines? AN lines do not work well for brakes. You can the brakes pressure guage to determine if the backs are ok also. You should get about 5 to 6 hundred pounds on the first stab if everything is correct.
No one that I know of has had a problem with the factory master when staying with drum brakes. Make sure that your master is not bigger than 7/8's. If it is that could be your problem. You may have chosen a master that was designed for disk brakes if you don't know the size or application.