Hey MrCJ,
Nice serial...This number would denote a model 4 non Automatic (std). Images will determine if this serial is accurate to your mower. The model 4(std)is the base form of the failed/deleted model 4 automatic (Predicta). Manufacture date should be approx 57/58. Check the model 4 automatic forum on this site and you will find info relevant to your model. Look in popular topics" on the left of screen in the home page.
Regards Mal.
