Did you check your vacuum pump for a leak? I had bad blow bye and thats what it was, goodluck.:Cheer:
My brother's truck had terrible blowby from a vacuum leak. Part of the hose mounted on the firewall directly under the cowl was dry rotted and it broke apart. You could hold your finger on the end of the hose going to the pump and it would immediately stop the blowby.
My vacuum pump is just along for the ride. Its in a superduty, I just have to check my block off.