Originally Posted by GomangoCuda
There are tube seals made for this

Milodon sold by Summit, Jegs, Mancini and many others
Summit

Much cheaper. Made in China copy?
Classic Industries


Note:. They install easier if you freeze them first.
Note2: Don't know if it is true but I read somewhere that they may not fit aftermarket heads that have beafier rocker stands.

Valve covers off for installation or just plugs and tubes...Thanks