[AdamHeard]

Well, the AndyMark gearboxes only have a 3.67: 1 reduction, So those won't work.

The KOP fisherprice gearboxes have a 124:1 reduction.

Also, you say 40 lbs but we need more information to do calculations. Is it lifted straight, is it a lever arm?

Is the shaft of the BB directly driving the arm, or is chain? If there is chain, you can easily add more reduction in the sprockets.