Truth Dyad Operator 4 1/2" arm

Sorry to hear the 39-315 didn't work for you. This operator's design, with the offset link arm riveted underneath the gear arm, looks more like the 39-171 to me. Now, the 39-171 also has a link arm that is 5" long. You have two options to start with: first, try installing the operator and see if it works anyways. Second, if it doesn't work, try re-positioning the stud bracket to see if it makes a difference.