I have not put any type of gauge on the crank case pressure, but I have blown air through the breathers and lines to determine that they are functioning. While excessive crank case pressure may be the source of the problem, I did have a severe crank case pressure problem with a sbc a couple years ago. However, the difference was, that it would constantly blow out oil pan and timing cover gaskets.....not intake gaskets. I am in the process of removing the intake, at the moment. I suppopse I could put the original intake back on the motor, and check the results. If the problem is corrected, that tells me 2 things....the new intake has problems...and never buy an intake at a swap meet.