tenrail,

I think you are missing a piece in there. The header shown needs to have either a pipe with a flange built in to mate with it like here

http://www.rcuniverse.com/market/item.cfm?itemId=54757

notice how the pipe has a flange where it mates directly onto the header.

If your pipe does not have this flange already, and it appears that way, then you need a pipe adaptor, these were common in the byron setup. Basically it is the first section of the pipe in the link above, only about three inches long. then you would connect to the other portion of pipe with the silicon connector.

you cannot connect this type of pipe to the header shown with directly with the silicone connecter.