The "valley tray" is the gasket-replace it. A little gasket sealer around ports and china walls is good, with a small dab of silicone at the 4 corners. Use fiber gaskets in addition if you are using an aluminum manifold.
The last time i did it, which was 16 years ago, all i used is the tray and sealant. Still like this right now. I will be switching over to an aluminum intake this weekend and wanted to know if everyone else did or did not use gaskets. I was always told to only use sealant because if you use gaskets on both sides of the valley tray that it throws the geometry off and would end up stripping bolts out trying to get them in..
