Until the mid-1980s symmetrical BB spindles were only found with single chain ring cranks. 124mm is proper length for a triple crank; a double would be 118-120. Here are a couple possibilities:
http://www.biketoolsetc.com/index.cg...=YS-BB98868124
http://www.biketoolsetc.com/index.cg...TH-7420AL68124