a gasket would be much easier and definitely less permanent. However, if you do it that way you are left with a unused passage in the head that will cause turbulence and effect the flow of the exhaust leaving that cylinder on each head. To maximize flow we melt the piston into the heat cross over and pour it about to flush on the valve end. By doing this you are able to take a die grinder and match the tunnel shape to the other cylinders so they have even flow.
