(another spelling): Gran Turismo, or Grand Touring, I think started with the Ferraris in Italy.
Grand Touring cars were popular in the early 1920's, too. "GT" was universally used in the early 1960's, and the Mustang almost got the "GTO" designation, but Pontiac grabbed it. It makes you wonder if different car company's engineers and designers had lunch together a lot those days...
The use of "GT" in GT/CS was a carryover from the Shelby name. "GT-350" came about when Carroll asked some guys at the Venice plant how far it was from one shop to another, and some guy said--"oh, about 350 feet". Thus, "GT-350", and thet rounded it off at 500 (GT-500) from the 428 engine size.
I think that the "GT-40" name might have been a poke at Ferrari back then, since they didn't sell to Ford in 1962. Enzo backed out at the last minute. The Mustang nose design was from a Maserati, and the Horse in the grille was another poke at Ferrari's "prancing horse".
However...we DID get the Marchal lights from the 350-GT Ferrari.
Hmmm....think about this: Would the "KR" in GT-500KR now mean "Knight Rider"?
Paul N.