hope someone can help. Dropped in a new 306 .upon start up the oil filter cracked at the base. Thought maybe bad filter. Replace it .started again and drove it home ,no issues. Took it out for a drive and rear main seal blew, ok maybe dry rot from sitting before i bought it. Replaced that ,drove it home no leaks. Took it out again and back of head gasket is leaking oil onto top of motor! And I found the pvc valve out of intake. Thinking too much crank pressure but I haven't put anything in the valve cover grommets yet. Don't want to replace head gaskets and have something else leak any ideas? Thanks