I am preparing to install front disc brakes on my 66 Chevelle, and am wanting to know where to purchase the wire connection that goes on the proportioning valve and where to run it to. The car currently has drums up front and no pro. valve or wires.

The wire goes to the Brake System Warning light. The connector may be a junk yard only part. What year valve are you using? If GM, I'd bet that any similar year GM vehicle will have the same connector.