There is (was?) a boat in Annapolis, hull #9, Ginch that was once a J/30 and won the NA's in 1981 with designer Rod J himself at the helm. Owner discussed with me the whether adding a masthead sheave and possibly a jumper strut would render it ineligible to be raced as a J/30. Don't know if he ever tried it but he might be lurking somewhere. Hard to say how a measurer would've treated this, but owner had already modified the keel with extension shoe for depth/stability and if I recall correctly latter modified the stern and/or rudder.
