I am installing my noss head and 20cc domes as we speak. I came across a question. When removing the old head, do you take off the head gasket or leave it on with the new one? Please somebody help quick because I am in the process right now! Also, will I need to rejet? dlnoss said that I have to mix with race gas now but did not say anything about rejeting. I am at sea level. Thanks for all the help HQ'ers!