Too much pressure in crankcase

[WD69FIREBIRD]

I just picked up my 69 Firebird after a 2 year rebuild yesterday. I keep blowing the dipstick out. Along with some oil. I locked the dipstick in and now blow oil out of the rear main. Too much pressure I thought so I checked the PCV valve to make sure it was hooked up and free. Appears fine and has suction on it. The rubber grommets is a baffle. Rubber plug has a slit in it the PCV valve goes into. Oil everywhere all under the car. It is a 455, hydraulic cam, edlebrock high performer heads. Motor was built a year ago so it did sit a few months before it was ran. The car made some rounds around town from the shop, to upholstery, to window tint, muffler shop etc...I ran it down the highway going from 40 to 80 about 15 times trying the seat the rings. Trying to get from high to low vacuum. I step on it and she blows its top. Any advice?