All the cast crank balancers I've seen have a note on the face to use with a cast crank on the face.
Not all, this is a balancer from a '72 cast crank 400. Very easy to mistake for a 6-pack, the difference being the thickness of the elliptical weight...the 400 is about 3/8" thick while the 6-pack is 3/16"-1/4" thick.
