As part of a restoration of a 73- 500 that will soon begin, I am gathering all of the tools and things that I will need to get the job done. One of the necessities that I used was a carb balancer called "Carb Stix". A low tech but very useful tool that kept the 500 running well. Over the years, the mercury has evaporated. Does anyone know of a source for a small amount of mercury , or better, a more enviromentally friendly substitute? Any help will be appreciated.