Thanks Mike but these heads have 2 openings at each middle ex.pocket,(with the heads upside down and valves out of the heads, looking into the ex.pocket you see two openings).Meaning that every time the ex.valve opens hot ex.is pushed #1.out into the ex.system,headers,mufflers,etc. #2.hot ex.is also pushed into the crossover port of the head which would connect to the intake manifolds crossover port to provide intake manifold/carb heat. And with the intake manifold that I want to buy having that section of the intake manifold cut out,the exhaust would just blow everywhere. So I need to block it off or fill the head crossover opening.