Of course, Elvis never cut a vocal track for FIRE DOWN BELOW...but a couple of years ago, there was a singer by the name of Terry Mike Jeffery who recorded the song with Jerry Scheff and the TCB Band for an album that Jerry was selling on his website. I just checked and the CD is still listed there...here is a link:
I picked up a copy of this CD (thanks to my buddy Joe O.!) just so I could hear the lyrics to FIRE DOWN BELOW and it's a GREAT SONG!!!
Hope this helps you out!