Slant 6 engine ignition timing stays retarded.

Since this is a change, compare the new to the old. In particular the distance from the mounting stud to the pickup center. Can't tell you why there might be a difference but there's only a few parts that could change the signal relative to the rotor tip and cap.
That's interesting and a great idea(I never would have thought of that). I'll do some measuring. That's why I don't rush to throw away the old parts. Thanks!