Itchy

Howdy ! I have one question for anyone that has messed with IN frame Master cylinder and brake boosters. I am building a 1949 chevy, p.u. That I swapped out the frame and running gear for a late model truck. And installed a chevy model delco early 70s cast iron dual master cylinder and brake booster in the frame below the cab.. kind of like the 49s had. The frame I swapped the 1949 body on to. Is a 2001 Chevy S-10 So it has disc brakes front and rear. With the master cylinder,brake booster and lines installed, it looks great. Just not able to drive it yet. But I was told by 2 old timers that it will work. But not like it should. They were saying with the master cylinder in the frame. Brake fluid will tend to run back to the master cylinder from the brake calipers front and rear. Not having good brakes And to correct this i will have to install like a 2 lb. Residual check valves on the front and rear brake lines near the master cylinder. Has anyone ever done this type of brake system.