Yeah, part of the problem here is that there is nothing such as 2-speed wipers in a '65 Dart unless you could "on" and "off" as two speeds...that's actually 1-speed.
I don't have facts to argue. I know Dart was the low dollar offering but I want to believe 2 speed wipers were available.
There is a interesting movie about the invention of intermittent wipers.
Aftermarket never got into these because there were too many variations and not enough demand for any of them.
Turn signal switches were dealer only item for many years also. I think that's because it is/was dealer installed in most cases. Some of those are still not available in aftermarket.
