You could have it re-hard chromed and ground. There is a sleeve kit that can be installed.
Be advised that the large diameter of the shaft is nominal (unmachined) material diameter and it not concentric with the machined surfaces. If you try to indicate or chuck on this surface, it will cause your impeller to run out or the shaft to bind.
Honestly, if it is not Aquamet (AQ) or 17-4 stainless (both are magnetic), I would trash it. Stock 304 stainless (non-magnetic) shafts should be easy to find used. Just make sure that your driveline yoke slips on all the way to the snap ring to ensure that the splines are not twisted. A good new 17-4 shaft isn't all that expensive.
