Recently (since warmer weather) I've noticed a strong smell of gasoline in the garage after shutting it down. I strongly suspect the carburetor is percolating as I have no spacer under the carburetor (Edelbrock Performer 600). Has anyone got experience with the best type spacer to use? My quick web-searching reveals there are several configurations and at least two materials. Even Edelbrock shows several different spacers on their web-site.