That would work. You could also use RTV to seal it.Thinking out loud here…what if I got some mild cold rolled steel and made me a “cap” for #2’s intake port? Use some rubber gasket material to insure a leak free seal? I don’t believe I have a clamp that would fit over the head but I could drill a couple holes in my plate and use the intake manifold bolt holes to tighten it down. It would quantify to me if the valves are leaking, or it is indeed the bottom end.