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.
Just guessing, but it might be Yes performing "Siberian Khatru" opening with excerpts from Stravinsky's "Firebird Suite".
If YES as per onhwy61, check out YESSONGS' opening track to confirm (or not).

Another possibility, The Flock (Jerry Goodman violin)...
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.
Why not contact the radio station and see if they have either the information or an archive?
There’s a great ‘Married... With Children” episode in which Al goes on a far flung quest to find out the name of a song he heard on the radio, “Anna.” It was absurd in the show even though the song had just played in the car on his ride home that day. OPs post takes that absurdity to new and glorious heights...
I'm glad I'm not the only one who's driven myself crazy trying to find an obscure song. I would take the search right to Muncie. I'm sure you'll have an answer within a day or two. Please keep us posted. Joe
Could it be New York Rock & Roll Ensemble's track called Brandenburg?  I think the album Faithful Friends was released in 1967.
I think the electric violin has to be the clue here.  Please let us know if you ever find the answer.  I'm shooting for an early progressive bands called "If" or the Italian band PFM.  
Was it a long song? Was the radio station a free format station or top 40?

Atom Heart Mother by Pink Floyd released in 1970 kind of fits your description
See what were the top 100 songs from that year or the previous year in that genre.