Redline

Hello everyone I have recently run into a problem finding Liners for a customers 1971 ENDT-675 engine in his R600. Before I started doing an in frame on his truck I called the local engine shop and they said that they would be able to get the parts no problem. So I pulled the liners out and now they tell me that they cant get liners for this engine and that nobody will have anything. Is there does anybody know anyone that deals with NOS engine parts for this vintage of engine. Thanks in advance.