This happened to me once on a 360 truck motor. We were making the move from Ohio to Arizona and I made a nasty puddle in a motel parking lot. Changed out the filter, screwed the new one real tight, dumped in a quart of ATF, filled it the rest of the way with
oil, and drove the remaining 1500 miles without any problem. I don't recommend this for your 428, but maybe a quart of Rislone will give the added detergency needed to free up the pressure relief valve. My 2¢.