Nobody knows how many are left. The only possible way to find out would be to get the vins of every currently registered 1974-1978 Mustang from all 50 states' DMV and/or DoT and then run a Marti report on each and every one to find out which are/were Kings.
Even that that wouldn't account for unregistered cars in barns, backyards, private collections, or shipped overseas.
The reason they're not that valuable is because the Mustang II still carries an undeserved stigma that Ford stuck us with in 1974 by not including a V8 in it that year. Doesn't matter that the '75 and '76 cars had as much power as a 302 '73 and weight a LOT less, ignorance is bliss, and most people are happy hating the II out of ignorance.
Even that that wouldn't account for unregistered cars in barns, backyards, private collections, or shipped overseas.
The reason they're not that valuable is because the Mustang II still carries an undeserved stigma that Ford stuck us with in 1974 by not including a V8 in it that year. Doesn't matter that the '75 and '76 cars had as much power as a 302 '73 and weight a LOT less, ignorance is bliss, and most people are happy hating the II out of ignorance.