Just to add to the data points: Top to bottom- 1966 P13, 1971 P13, 1983 Waterford Standard




The fork rake and frame geometry changed on the P13 sometime in 1971. [MENTION=40306]cudak888[/MENTION] did a comparison of his two 1970s chrome P13s back in October 2010.. Here is a closeup of the forks on these beauties, a '70 and a '72.