I have been informed that a few people have questions regarding my original post and that I may not have been very clear in how the O ring seats so I want to elaborate a little bit further.
When tightened, O rings compress. That is why you use them. This compression allows for a tight seal and in the case of a throttle body connection you want to avoid any air leaks, hence the reason for the O ring. When engineering an O ring groove such as we have in the intake manifold. it is important to know the rate at which the O ring compresses. You don't want the throttle body to just sit on the O ring, yet you don't want to overtighten and crush the O ring either. If a foreign object or additional sealant is introduced into the channel that the O ring sits in this will cause excessive pressure as the O ring and the CNC machined channel were not designed to have something else in their space. Think of the saying 10 pounds in a 5 pound bag. The additional material has to go some where and it's going to follow its path of least resistance which is the thinnest part of the casting, hence the images you see where the aluminum is either cracked or warped from the pressure built up from the RTV silicone.
Another question had come up regarding the amount of torque that had been applied to the bolts. Keep in mind that this is a cast aluminum intake manifold with 4 6mm bolts attaching the throttle bodies. There isn't much torque in this application.
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