67 Corvette Brake Issue

[72-SS-L48]

Good Evening,

I'm working on a 67 Corvette. A little background, a few years ago the previous owner did brakes on the car. Stainless steel lines that still look good, the rotors look fresh, calipers aren't leaking, and hoses are still pliable. The issue is the brake pedal goes straight to the floor and the car barely stops. Today I pulled off the wheels and attempted to bleed the system. Believe it or not very little to no fluid came out of the bleeders. And yes the master is full of fluid. The master is not original, nor leaking but it does look rusty and old.

Right now I'm thinking there is a clog stemming from the master and I'm ready to change the it. Before doing so, can anyone shoot any other ideas to look into to?

Also could it be the distribution block located directly under the master? This is a standard brakes car. Not PB.

Thanks,
Dave