My 1958 dodge D-100 uses that type of filter, It goes in an external canister. [FONT=Arial,Helvetica]The 230 engine uses a bypass oil system .
[FONT=Arial,Helvetica]The oil pressure relief valve is designed to divert oil to flow through the filter when the pressure exceeds 46 psi (and when the temperature is above about 135 degrees F)
[/FONT][/FONT][FONT=Arial,Helvetica]This feature helps deliver oil pressure to the bearings as soon as possible after starting an engine, since during those few seconds while the pressure is low, all of the oil pump's capacity can be routed, via a shorter route, directly to the bearings. When the engine oil is warmer (and thinner), it can pass more easily through the filter, so the valve allows it to be diverted through the filter.[/FONT]