Vacuum Pump

We are in the process of restoring a 74 Duster, have the drivetrain finished but are experiencing a Brake problem. We have Power Steering/ Brakes. Took it out on the road last week & ended up with no brakes. Have been told we need a Vacuum Pump(they are quite expensive). On the old valve cover that we didn't reuse from the 360 we rebuilt, there is a Vacuum Amplifier,wondering if that's what we need? We have a 484/284 Cam installed. Any input on the best way to resolve this would be greatly appreciated.