I'm getting ready to replace the Y pipes in my 1971 Trisonic merc 888, Ford V8 302. I have new O rings and bolts, but should I also use a sealant between the exhaust separator and transom plate, and also between the exhaust separator and the side pipes? If so, what sealant should I use? Since my current leak is at one of the joints, I want to make sure it stays sealed, and the O rings just don't seem like they would be enough.