Shadi, why switch to an inferior fuel? There are many disadvantages to leaded fuel like hazards to your health, spark plug and engine life. Lead was never required in gasoline in the first place. It was just one big conspiracy. Have a read through http://past.thenation.com/cgi-bin/framizer.cgi?url=http://past.thenation.com/issue/000320/0320kitman.shtml
if you are interested.