When I pulled my heater for repairs I simply put a piece of copper pipe in the ends of the hoses and clamped them. I then suspended it from the rad support bars for the interim. Ran it all summer that way.
However as is written above just make a simple loop or put plugs in the pump. no problems.
Incidentally I keep that piece of copper in my on board tool box in case the heater blows while I am away from home.


1949 Chevy 1/2-Ton
"Sedgewick"
In the Gallery
1989 Caprice