Editing GTO muscle car myth

Recently I read an article by an auto magazine writer, who was writing about the Chrysler 300 "letter series"
of muscle cars. He imparted many interesting thing about those cars. He then said the weren't muscle car because
they were loaded luxury cars, he determined that a true "muscle car" had to be more affordable to more people.


Lets give him and similar thinkers that.
So do any of those similar thinkers or those, who on general "say so" of supposed auto affectionatos,believe their
claim that the "muscle car" never existed until Pontiac invented the GTO, have an answer for the 1955 and on, 
PLYMOUTH-FURY, DODGE D-500 and DESOTO-ADVENTURER? These were all were called Super Sports way before Chevrolet
eventually, smartly and to good advantage, copyrighted that moniker for there own line of muscle cars.
Matter of fact I always felt the SS's even predated the GTO's. Someone please give us some research on this.


'''The main item ''' to define the beginning of the 'muscle car'  was the breaking of the number of  cubic inchs per pounds rule the big 3 had.  The Tempest received the larger engine and became the GTO.

I believe the rule was 1 cubic inch per ten pounds.  The GTO did not weigh 3800 pounds with the 389 engine...  or maybe this rule I speak of is a myth?