Here is the locking valve that I am using.
As of today, 07AUG17, it is available here:
< Metro Lock Valves: MFG No. 409-08, Double Circuit, 10 GPM, Inlet/OutletSAE 8 Ports, 3000 PSI, 280367 >
You might be able to find it cheaper elsewhere.
This is a picture of the valve on my car. The...