Carl- it's quite likely I have that if you want to get me an Oregon or Herr part number.
That there is the root of the problem. Can't find a part number except the cryptic Lombard (maybe) stamped on the drum. N156 A7
Found a .404 on evilbay but, we are not going there as we have almost all 3/8 in the stable.
Clutch is a Hoffco Comet. Drum inside diameter.......3" on the money. Drum depth...... 0.650",. Bearing bore (outer race for the roller brng.).........0.6875" (11/16"). Length of bearing........0.473".