Mockup & see how the end gaps compare to the cork gasket thickness as deck height/milling/head gasket thickness can put that anywhere & using cork end gaskets that are a hair too thick can cause a front water port leak over time. If not using the supplied end gaskets clean the metal surfaces SQUEAKY CLEAN before applying black RTV. I prefer to cut my own end gaskets of the right height & use some gasket cement on em rather than no gaskets and RTV. As said composition gaskets on the side gaskets. I use Permatex #99MA "high tack" the red adhesive in the spray can on em. It goes on light/even and is extremely tacky which is just what is needed to hold those side gaskets in place