To me, having the pressure cap on the pump/block discharge side would be the "cause" for cavitation at the pump suction, with the increase resistance of the radiator the contributor. Replumbing the coolant to place the pressure cap on a true expansion tank on the pump suction seems to be desirable. Thus, keeping the pump suction at a constant, not decreasing pressure with increasing flow. Turbulence in the pump inlet "elbow" would also contribute to cavitation and using a vane in that elbow be beneficial. JFB -----Original Message----- From: DeTomaso [mailto:detomaso-bounces@server.detomasolist.com] On Behalf Of Ken Green via DeTomaso Sent: Tuesday, July 26, 2016 15:20 PM To: L GRAY; hoppe1@cox.net Cc: detomaso Subject: Re: [DeTomaso] Cooling system ...cause cavitation at high RPM in the water pump in a Pantera...