1966 Dodge Dart GT Factory Ride height?

I take that back. I just looked at my 66 service manual. The spec is the difference between the distance of lowest point of the LCA pivot and the ground and the distance between the lowest point of the lower ball joint and the ground. The spec is 2" for non- "heavy duty" suspension and 2-3/8" for 66 Darts with "heavy-duty" suspension.

Here is the wording from the FSM:

Measure distance from lowest point of one adjusting
blade to floor (Measurement A) and from the
lowest point of steering knuckle arm, on same side
(Measurement B

There is a nice picture in the manual that illustrates what measurements you want. You can get a free copy here:

http://www.mymopar.com/index.php?pid=109