I just went through this last week for my 69 Fury III. I looked everywhere and nothing. Long story short the one I had they used in a 69 and 68. Checked rockauto for the 68 and they had one in stock. I must have gotten the last one as now those are out. I checked for a 73 Newport there for you and out of everything. I also checked Rockauto for 68 Fury brake boosters all the way to 73 I believe and all out of stock. Napa ,and all the major auto parts places were out too. What I got is a Cardone, not the best reputation but I will send my old one in to rebuild at Dewey's in OR. Here is a link to my topic if interested. Good luck and don't throw your old one away!