I have had issues with the same thing and in the end I O-Ringed the intake.Fortunately I was able to do that myself.I ran one of my blown engines with just an o-ring and it worked fine.The one I am running now is O-ringed and also running that gasket which has also worked.I was told to try this from a blower shop and it seems to be fine.Also the torque specs are important on the manifold studs.