Thanks, but since the valve is gone, all the heat would escape through the exhaust so overheating shouldn't result. I guess the downside would just be no preheating in cold weather.
Steve
Not exactly. With the flapper missing exhaust will be allowed to go up and over the intake runners and down the other side possibly resulting in a permanent too hot condition. This was discussed recently on the HAMB and the suggestion over there of using a pc. of sheet steel shaped like the gasket and placed between the manifolds may keep heat down and improve performance.