Hello folks, I've been reading this thread about oil filters for a bit and I have to add my observations. Both the 161 and 226 engines used in Kaiser and Frazer cars have oil pumps that feed the crankshaft main and rod bearings first, then the flow is to the camshaft bearings and tappet galley. The 161 has the oil pressure relief valve in the oil pump and the 226 has the oil pressure relief valve in the block main lower oil galley. The oil filters are fed after the oil is fed to the mains, rods, camshaft bearings, and tappets. The oil filter element provides enough restriction not to drop the oil pressure in the engine. In other words whether or not you have a factory approved oil filter will not, cannot starve the main, rod or camshaft bearings of oil, because these areas are fed first. There would have to be no element in the filter housing to even begin to lower the oil pressure because all the oil flow and consequently oil pressure does not go into the oil filter. The bypass oil filter feed galley is after the tappet galley. I myself would rather have a partial flow oil filter than no oil filter. If you have an engine with a bypass oil filter that has low or no oil pressure, you probably have worn main, rod or camshaft bearings. The cause is probably from improper maintenance, abuse, wrong oil, or just plain worn out parts.