This is an interesting Champion Spark Plugs sign.  It's double sided, which is interesting because it has a rolled edge, and you would normally see a single sided sign like this.  It has patina, is painted metal and just has the classic look.  It's definitely an older sign, it has the look of a sign from the 1960s-1970, that is just our guess of course, but a neat piece.  Reminds me of walking into the shop my dad worked in during the 1970s and seeing signage just like this.
 
This version of the logo was used from 1959-1974.  
 
Measurements:
58 inches wide
33 inches tall