Not much information is available for the clip below. But one sign in the parade reads “Adolph Hitler is Alive and Well in Florida” which is probably in reference to Anita Bryant. Bryant’s anti-gay “Save Our Children Campaign” began in 1977 so I think its safe to date it as 1977 or 1978.
As you can see in the clip. Shirtless guys, drag queens, floats, and performers in Central Park. Not a far cry from today’s PRIDE.