Sometimes the rings can hang up and the manifold doesn't make a good contact. If there appears to be a space between the intake manifold ends and the head then that is probably what happened. I find it necessary to loosen the for bolts holding the two manifolds together untill the manifold is snugged up to the head. I keep the gaskets in place by using the rings in the head and inserting two of the smaller bolts in the two holes near each end of the head. The gaskets stay in place and the bolts are replaced after it is stable.
