A "T" piece in the water pump inlet line is what VP did on the later engines. They connected that to a garden hose type connector, the hose retained in place using an exhaust manifold bolt. Hopefully this link works.
http://www.marinepartsexpress.com/VP_Schematics/GAS/5.7Gi-E_5.7Gi-EF_5.7Gil-E_5.7GXi-F_5.7GXi-FF_5.7GXil-F_5.7OSi-D_5.7OSi-DF_5.7OSXi-D_5.7OSXi-DF/COOLING%20SYSTEM/Seawater%20Pump%20and%20Hoses%20%20Early(0).pdfWhatever end fitting you use, whether it's outside or inside the engine compartment, it needs to be airtight when not connected to a hose, or else it will suck air in.
I could never get a good connection between the VP garden hose connector and the garden hose connectors available in the UK. So, I removed it and replaced it with a ball valve and a male quick release coupling (the "Gardena" type). It's now easy to click on a garden hose. When not in use, that's capped with a blanked off female quick release coupling ( and the ball valve is closed). Due to the extra weight of the ball valve, I put a slightly longer hose on and made an additional stainless right angle bracket , the whole assembly is attached via a riser bolt, using the original bracket in the diagram.