I just installed a set. I did use a thin coating of the copper sealant. I leaned the hard way to always use some sealant from now on. They do not leak.



I did have an issue with the felpro gaskets, I'm not sure why but the ports were too large and I had leaks on many cylinders. The Mr Gasket one is behind with a smaller opening. Maybe I did something wrong, but the felpro ones came with the 360 complete gasket kit? All the other gaskets worked.