This is a .062 block off plate and gasket for the large end carburetors on the Tri-power intake manifolds. These can be placed under the throttlebodies if you decided to leave the carbs on the intake and have the end carbs be nonfunctional. Not something we want to see! If you have issues with your end carburetors check for vacuum leaks. I also have listed in the shopping cart for $30.00 each aluminum plates that are 7/16" thick. These thicker plates work great to block off the front and rear carburetor ports for tuning /setting your center carb. You can isolate your carburetor to determine if your issue is with the center carb. or the end carbs.