I bought mine from Summit, I think it is a Mr Gasket with a billet looking knob for like $30.00. They fit in the block pretty tight, so you will probably not have to use any RTV. Don't feel bad, I broke mine off in the block removing the exhaust log. I used a set of tubing benders and bent the tube to stick up behind the log at the rear of the engine to aviod breaking it again. If you have logs, you might want to think about doing something like that.