There are a couple of things to note here. First is how to measure axle drop. With a straight-edge placed across the flat of the perch boss on the '42-47 axle at the bottom of the picture, measuring up to the bottom of the kingpin boss reveals a drop of 2 inches. The '37-41 axle above has a drop of 1 1/4 inches and the Model A axle has zero drop. Secondly, these axles are all on the same centerline, so note the different widths, as well as the different distances between perch bosses. This means unless you split the wishbones, they'll only fit an axle from the same-year car. These were all found in my garage, and, unfortunately, I didn't have an early "heavy" '32 or '32-36 axle to show, but they both have similar lengths to the A axle between the perch and kingpin bosses, and it should be pretty obvious that these have more area to stretch and drop than the later axles.