1965 Dodge Dart Charger

I found this old picture I posted back in 2008, poor quality due to resizing it....but you can see the extra tall master cylinder cover but also, the MC is bigger as well....another member pointed out in the old thread that it is a pretty rare part.....why would it be bigger? I have never seen another one like it. Car is a 66 Barracuda S with manual discs.