Im guessing the opening your talking about are the heat exchangers in the heads. It is my understanding that they are mainly just for warming the intake manifold for choke operation. I know if you block them, your choke may not work 100%, but there is also some performance gain to be had for the simple fact that the intake doesn't get as hot. I can say as to why the gaskets you have dont have the openings. Perhaps your gaskets are for a different year engine that did not have the risers, or they were made to block the risers off. Hopefully somebody else will know a bit more.
Bookmarks