I cannot tell what that is, but it might be an axle bumper (rear axle bumper, maybe)?
1954?
rear axle bumper rear axle bumper kit 1940-1954 front axle bumper (it goes inside a cast housing)
I have found that the reproduction rear axle bumpers are much smaller than the original.
I have received two sizes of front axle bumpers. If there is a 1956-59 front axle bumper, it might be longer than the earlier one.
