Gruen states that the 440 Curvex uses the same parts as the 430 except for Ratchet Wheel, however that's a gross summary. Closer examination shows these differences
The ratchet wheel's text (mechanically they are the same)
The pillar plate has differing caliber stamps
The pillar plate on the 440 is "curved"
The ratchet bridge with the serial number
The train bridge has different text and design but mechanically the same
