I know that Ballenger Spars makes custom spars for a variety of boats. They may be a resource.
The challenge of older boats is that the design information from the manufacture is rarely available. They would be worth contacting to see if they can help.
You are not limited to any specific original manufacturer. Selden Spars in Europe might be able to fit a mast to your boat.
www.seldenmast.com
You will need some dimensions of the current rig to help a manufacture to build a replacement. Information like that provided by SailboatData may help.
sailboatdata.com