went thru this myself just a couple of months ago... finally broke down and pulled the dist. marked everthing with positions and took some photos before removing... came out easy; knocked the plate loose using a small pick thru the little hole in the bottom of the dist housing after removing the pertronix sender and other connections topside...
mine had frozen weights and springs that prevented any advance from happening... generously soaked that end in WD-40, Gunk and carb cleaner and finally got them freed up. now have advance...
it can be done! take your time and don't come near it with your GBF screwdriver!!
"God Bless Texas"location: Houston,TX