I rencently went to change ( remove ) the "stock" OPSU out of my 5.7 and it seems that the people that put the motor in tightened the bolt so much its hitting the block where the oil filter goes, and to make matters worse the bolt head has now rounded off.. I've tried the OPSU socket and got nothing, im at a total loss on what to do next. Problem solved. I used a sawzall to cut the bolt, knocked out teh diaprhagm and took it out with a pair of vise grips overall MAJOR PITA