The four bolts have a sealant, I decided to not use the old seals. The bolts "pass thru" manifold vaccum so if the bolt heads leak then it sucks air. After they wer tightend it was very evidant that the sealer is put on there for a reason. Looks good, I'm almost done with mine and do recommend the GM intake kit.
After doing this whole job, I kick myself in the butt and highly recommend one to simply tighten at least the outer 4 bolts (in my case it would've fixed the problem) I should've guessed it when I heard that the "bolts come loose" anyways, mine wasn't too late to catch it in time.
Two things also come to mind after seeing things:
The machine job on the intake is terrible with a terrible steps, finish, and hopefully the angle is correct. If I had to do it again I'd get a very light pass done on a grinder as the smooth surface would probably be far more forgiving with metals sliding up against the gasket. The head surface and uper intake wasn't nearly as bad a milling job.
The second thing is the design with in effect 1 bolt per 5 ports is bound to give more trouble than a design with 2 effective bolts per port. The 4 middle bolts help somewhat and probably do more to control flex than anything else. I'm surpised it does as good as it did.
An engineering marvel that went slightly off kilter, lol.