Here is a link I have had bookmarked for a while that discusses the various Marhoefer sets of the '60s. Jon Hardgrove really is the man when it comes to older racing sets.
http://www1.coe.neu.edu/~dan/marhoefer61/go.html
Here is another thread in which Jon Hardgrove details, year-by-year, how many cards there are in each of the Marhoefer sets.
http://www.network54.com/Forum/52660...s+to+the+1950s
Here is another link I have had saved for a while in which Jon Hardgrove shows examples of many different older sets and gives a blurb about them.
http://www.thecarburetorshop.com/AutomobilecardsUSA.htm
Another Jon Hardgrove thread in which he extensively discusses the Marhoefer sets, checklists, etc. Great reading for those who want to learn more about the Marhoefer sets.
http://www.network54.com/Forum/52660...anted+to+know)