1957 Evinrude Johnson Outboard 5 1/2 HP Lower Unit Gearcase 376791
Driveshaft is 17 1/4" (from the top of the gear housing to the top of the driveshaft)
This is a good working lower unit. The oil was clean when drained.
You will need to replace the water pump impeller and re-fill with new gear oil prior to use.