I remember an old story about putting some large washers in the connections where the water hoses connect to the block to slow down the flow of water to help cooling. Has anyone else heard that story?

 

Yes, but only in the early series flathead V8's cause they didn't have provision for thermostats and had less efficient waterpumps.

In the later series flatheads the thermostats provide about the same amount of restriction as a large washer with a 5/8" hole.