I'm going to be replacing the exhaust manifold to y-pipe gaskets on my truck and wanted to get some feedback from others on orientation and use of sealants. The "gaskets" are more accurately described as two pieces of tin crimped together. Does the flat side go toward the manifold or the y-pipe? Also, is any sealant needed or just clean up the surfaces and torque them down? I'm used to exhaust gaskets that actually have something to them like the ones between the head and the manifold. I did these previously (like 15k miles ago) but it looks like the drivers side is leaking again so I want to see if I screwed up.