IMO - to be crowned "King of the muscle cars" you have to look at the available cars at that time and what came standard/mandatory as far as options on those cars.
Yeah it's great that you could order a 1969 Mustang 428 SCJ Mach 1/Sportsroof with a 4.30 Detroit Locker rear but out of 130,000 built only 1046 did.
The 1970 LS6 Chevelle was a great muscle car. But it came standard with a 3.31 non-Posi 12 bolt rear.
These are factors that should be considered when that crown is awarded. And as far as I am concerned there are only three contenders: