Here's my two cents. I contacted sew-classic about the 66 bobbins being too big. She replied that hers are checked and will fit the older machines. All twenty that I bought work like a charm.
Aren't I sad today. I'm visiting DD north of Baltimore and brought my 1963 New Home to quilt a project. Well, the motor died today. For awhile she would take off and sew perfectly if I just bumped the wheel. Now she won't do anything. Its not the machine. With the belt removed I finished the seam by spinning the wheel by hand. And the motor does nothing even with the belt off. Sigh. Where in the world will I find a motor for Myrtle?