Brent,
FE intake manifold fitment can be a pain in the booty. You have the intake flanges to worry about, the ends, and then because the intake makes up part of the valve cover flange, you have to worry about that too. The fact that the intake gaskets are submerged in the
oil doesn't help.
A good quality gasket is always necessary, something like a Cometic, Edelbrock, Mr. Gasket, etc., and it needs to be used after the intake flanges are deemed flat, straight, and at a parallel angle to the head.
I glue the gaskets down to the head, and then use a little sealant around the ports before I set the intake on. You have to also pay attention to how centered the distributor is in the hole, because if it's off, it could cause the distributor to be hard to turn, or could cause a leak on one side.
I concur with the difficulty level of working with an intake manifold on an FE, it is a PITA
. I may not have worded how my mechanic was explaining it to me regarding too much lash limiting the full effect of the cam. My mechanic was quite anal about measuring everything and checking all clearances between the manifold and the head. He ordered 4 different thickness gaskets to make sure that he had the right one. The Mr. Gasket one turned out to be the correct thickness. I think that he only charged me for about 1/4 of the labor that he had in to it. The previous mechanic had used way too much sealant in multiple areas, I think that he had 4 hours into cleaning the manifold and head alone.