Hi there, question regarding the Temp-A-Cure coolers (http://www.holley.com/types/Temp-A-C...%20Coolers.asp). Are the plugs a certain direction or can they be reversed? Would be installing two a certain way (in which, the plugs are facing inward) so wondering if it's unidirectional or if it's OK to mix up the inlet/outlet ports. Thanks for your time.