325 Poly Oil Filter Adapter

57chizler Posted 2016-02-09 6:09 PM (#503704) Subject: 325 Poly Oil Filter Adapter Expert Posts: 3778 Location: NorCal I know that the Chrysler Hemis need to have the block oil gallery check valve removed when converting to a spin-on filter but is the Dodge the same? I looked through the Dodge service manual and see no mention of the check valve. wayfarer Posted 2016-02-10 11:32 AM (#503781 - in reply to #503704) Subject: Re: 325 Poly Oil Filter Adapter Elite Veteran Posts: 888 Location: Peoples Republic of Oregon There are several variations of the oils system: Some blocks do not use the pressure relief/anti-drain back assembly; some blocks only use the anti-drain back portion; some blocks use both. I have seen early 331 w/o the assembly; I have seen many low-deck Dodge/DeSoto w/o the assembly and have also seen many low-deck with just the anti-drain back. I do not know the 'why' part for the variations....... I don't have any bare tall-deck blocks at this time so cannot offer to check. You do not 'need' to change the oem assembly (if you have it) when installing a late filter. The oem design will still work. You might just end up with two pressure reliefs and two anti-drain backs.... also, NOT ALL late filters have anti-drain back features. A practiced hand can determine if the oem parts are in the block vs a non-drilled block. If you have plans to drop the pan and rear main cap then the process is infinitely easier.