Just wanted to make everyone aware that you cannot necessarily install oil pressure and return fittings on the Fluidyne 30317 double pass oil coolers on red painted ports. I am in the process of going thru this install myself and upon receiving my new double pass oil cooler, I reviewed ports and noticed I could see right thru to other port on red painted ports. I viewed unpainted ports and found plug insert halfway inside of tube(after first three rows) as should be. I called Fluidyne and one of their tech persons told me that every once in awhile the incorrect ports are painted red, so you will need to look into your ports to make sure what side insert is installed. Hope this helps!