oil filter blowing out

I am working on my 1997 Oldsmobile Cutlass; it is an automatic; 3.1 Liter; with 155000 miles. I recently had a lifter that was sticking and therefore replaced the lifters and had the heads resurfaced. While the engine was apart I noticed excessive sludge build up in the lifter valley and head area. I cleaned the lifter valley and flushed the pan the best i could without removing it prior to putting the engine back together. In attempting to start the vehicle now the oil filter gasket blows off the car. I have tried 3 different types of filters and same result with each. My question is could sludge have plugged the oil pressure regulator ? Any help with this issue quickly would be wonderful. Thank You...