just adjusted advacne on my AC Delco disributor. I did it once before on my other Tr7 and had forgotten just what a terrible job it is. I eventually did it with a regaular 11mm ring spanner (tried a fancy flexible racket ring spanner but the diameter of teh head is too big to fit over nut as it fouls distributor body). However, to get some access I remove air box and air box backplate that fits to carburettors. I also had to remove the metal tubualr fuel line that connects both float chambers in order to get to the nut under front side of distributior. For thsi nut a ring spanner with flat end is best. Nut at rear / bulkhead side was easier, but better with a angle-headed ring spanner pointed down towards gearbox.
All in all an absolute pain. Perhaps a stubby spanner or one of those half moon spanners may make life easier...
1979 FHC pageant blue
1981 DHC triton green