Thanks SMCARNUT. I will consider the silicone.I would test fit intake without the cork end rail gaskets I think you will see a big difference. We toss the cork end rail gaskets and just use silicone make sure if you have pins on the end rail, they are removed also they can hold the intake manifold from sitting down also. Here is a picture of a 318 just so you can see the surface with the end rail pins removed.
View attachment 1716236792
Check again without the cork, just side gaskets only. I had a "similar" problem on my build. Mocked up intake with side gaskets only, then went to assemble with the cork front/back and it was a ***** to install as the intake now was a titch too high.
Cork or rtv for China rails is a personal decision. Either way let everything fully cure before adding fluids.
