[ford38v8]

As stated previously, you will get opposing opinions on this subject. Here's mine:

Today's oil being superior to oil back in the day is exactly the reason that an oil filter is needed today, as impurities are suspended in detergent oil, as opposed to settling out to sludge overnight with non-detergent oil. The impurities must now circulate until either removed by a filter, or drained for an oil change.

A bypass filter as you have on your engine, if properly set up, will filter all oil in 20 minutes at cruise speed. A full flow filter as used on modern engines, will pass larger particles than a bypass filter, and will dump unfiltered oil if pressures exceed the preset. For these reasons, your filter should not be removed.

The restrictor in a bypass filter is .60' and its placement on the inlet side is important. Pressure within the filter is greatly reduced by correct restrictor placement. Your filter may have been modified with a larger restrictor, or was incorrectly installed on the return line of the filter. You may also check for an accidental restriction caused by a crushed return line from the filter back to the engine. Also, the working engine oil pressure is directly affected by the size and location of the restrictor on the bypass side of the oil flow.

Every engine should have a relief valve in the block, to prevent over-pressurizing the system. If yours is malfunctioning or has been removed, or is mismatched to a replacement oil pump, this may also be a factor in your non-sealing oil filter.

Oil filters generally come with two different sized gaskets, to fit different brands of filters. They do not usually include the center hold down bolt gasket, which is easily made from soft copper by the user. Both gaskets are needed.