273 Exhaust manifold
Here's A picture of the stock gasket set. Note the surface width on the end gaskets. The surface on the head is ample but the end ports of the manifold are very narrow on the ends. Combined with the narrow gasket gives a very narrow seal. When installing the manifold, it's hard to position the gasket exactly in the correct location to prevent a leak. The only way to find out is to start the engine. If it leaks, you start all over. I took a little off the manifold, in an attempt to acquire a better seal but it's not enough. A fatter gasket would help.
Here's A picture of the stock gasket set. Note the surface width on the end gaskets. The surface on the head is ample but the end ports of the manifold are very narrow on the ends. Combined with the narrow gasket gives a very narrow seal. When installing the manifold, it's hard to position the gasket exactly in the correct location to prevent a leak. The only way to find out is to start the engine. If it leaks, you start all over. I took a little off the manifold, in an attempt to acquire a better seal but it's not enough. A fatter gasket would help.