They did in fact build the Shelby GT500 in 1967. The production numbers show that 2,048 were made that year and were powered by a dual-quad 428 cubic inch "Police Interceptor". It was rated at 355 horsepower (though it was actually closer to 400), and ran the quarter-mile in 14.5 seconds at 101 miles per hour or 14.9 seconds with the automatic. Top speed was rated at 132 MPH.
That would depend on gearing. I would say that most would run around 120 give or take a few mph. A lot of people think that the muscle cars had huge top speeds, they did not. A lot of speedometers were way off above 80 mph back then and when you combine a 1 to 1 top gear with a 3.73 gear, you are not going to go fast.
i own a repair shop,and i think in that year they were gt 350,s i don't remember one being a 500,,because i owned a 350 before,,but if built right they,d run anywhere from a 125 - 150,,mine ran 145 wound to the gills ,still got the speeding ticket to prove it also,it was given to me on the night of what we all called the big race there was over 60 races ran in one single night,and i won a few of them.and lost a few of them also,but the last ten races were title races i won a 1971 dodge challenger ,in one of the races,and still have it to this day,,good luck,i hope this help,s.
There were indeed 67 Shelby GT500's. Reputedly about 47 of them were made with 427 engines instead of the more usual 428's. Top speed depends on a few different things, gearing and aerodynamics being high on the list. Back in the late 60's, highly respected TransAm series Mustang racer Parnelli Jones once stated that even in race trim Mustangs tended to "hit an aerodynamic brick wall" right about 150 mph.
A GT500 with a 427 is no doubt a strong car but it's a safe bet that Jone's statement about 150mph would also apply. (No matter what they did in some movie somewhere.)