Jim, your Pre 65 trumpy doesn't run a mono-shock either.
I'd personally love to see enough pre 65's at Nepean to warrant a class on its own, I would enter this class. The rules for the classes aren't kept a secret in this series, they are on the entry form, it doesn't say anything about year models, just 3 requirements...... "air cooled, drum brakes and non linkage suspension. For this various debate in the past, I have now laced up drum brakes on my Astro and don't have any issues.