Inliners International Forums General Discussion Engines 261 lube question

HI guys,
Well after the dry piston pin fiasco, I"m ready to pre lube the 261 again prior to start up. Question: with the oil filter off, turning the pump slowly, I get oil out of both holes. I know the front one comes right off the oil pump but with no filter, why would I get oil out of the back one. If both are pressurized while running, how can oil pass through the filter?
Randy