Hi Kevin, I would say you don’t necessarily need a swirl pot but you do need an expansion tank – about 1 quart. I have a swirl pot but it is connected as an expansion tank as follows: The bottom connects with a ¼” line to water pump output; the top is connected to the rear iron (closest to PSRU), a pressure gauge, and T’d to an air valve for pre-pressurization and/or pressure relief.  The pressure cap overflow goes to a small collection bottle.

 

The top connection to rear iron is restricted to about 0.050” to remove air from engine block.  With this setup it doesn’t matter if the swirl pot is above or below highest point in system – just make sure the pot is only about 25-30% filled with fluid. The attached photo gives you some idea, but it is missing the rear-iron connection.  Hope this helps.

Jeff