Emerson, Lake and Palmer's "Pictures at an Exhibition" was released in 1971. It is a classical piece by Mussorgsky. BTW, my father was born just outside of Muncie IN. I used to spend the summers of my youth up there from the early 60's to the mid 70's.
Band of an instrumental piece played in march 1971 on a FM station from Muncie, IN?
Starts with an orchestra playing a sort of Overture that as it fades away from the background a drum and a bass guitar comes forward before the lead guitar or electric violin starts playing a fantastic rock piece, kinda progressive kinda clean rock. Haven't stop searching since march 1971 with no luck.