I m wondering about this.  I tapped and plugged the port on my 20B when I took the thermostat out.  I have filled the engine with coolant three times; twice on the dyno, and once on the airplane.  In each case I just filled the coolant and started the engine, and the coolant circulated just fine.

 

I have a connector hose that goes from the top of the rear housing into the pump housing (Pic 1, small black hose behind the primary injector wires) that connects the ports that were once used for turbo cooling. 
And I have an air bleed at the top at the pump outlet hose (Pic 2).  No special air bleed out of the pump.  Is your pump configuration different, or is there something else that allows mine to work.

Al

Hi Al,
The one thing I notice is that you're running a 13B water pump housing which is very different from the 20B housing.  (see picture)  So, I would say that my configuration is different than yours.

Hum-m-m; I guess I knew that.  Yes, it is quite different.

Al