Inliners International Forums General Discussion Engines 261 Remote oil filter line size

To prevent pressure loss, use a plug drilled 1/16" somewhere in the line to or from (not both) the filter housing.
Restricting the feed side from the block (the upper port) will slightly improve oil pressure on start-up, since it delays pressurizing and filling up the filter. It also protects the engine if the filter or housing leaks (which would otherwise drop system pressure if the restriction were in the return line).