Les - the 1957 141 and early 1958 142 washers were indeed helical drive, with the standard Bakelite helical drive agitator w/ filter. They used the AMP top and two-piece lid until late 1958.
By the end of 1958, early 1959, the updated top and single piece lid with the ball hinges was released.
Ben
By the end of 1958, early 1959, the updated top and single piece lid with the ball hinges was released.
Ben