Was there a circlip missing from the piston? Were either of the rings broken? Something def got stuck between the piston and the cylinder to cause that gouge.
You can get it welded and re-plated by lancourt, millennium, or uschrome. There are a few others, but those are the top guys as far as I know. Joe is right, by the time it's welded, replated, and fitted with a new piston, a 144 kit was not much further out. shame too, since the plating in that cylinder looks in great shape aside from that gouge....
J.