I have a number for a Mr Randazzo, who was, for many years, the Universal dealer in Port Washington. He retired some years ago, but still maintained his connections. When all else failed, he was the only one that was able to secure for me, the proper exhaust elbow for my M-12. You might try this phone number, and see if he (I think that his first name is Paul) is still involved. 516-767-1666.
I'd be interested to know how you make out.