I am disorientated by this discussion.

Does anyone have a 216/235/261 engine that has a distributor rotor that does not rotate clockwise? Is this what is meant by the "distributor rotation" (the rotor rotation)?

Does anyone have a pcture of a 216/235/261 in a conventional cab truck that does not have the vacuum advance mechanism on the right of the distributor? For the purpose of assuring correct orientation, here is a picture of the vacuum advance on the right side of the distributor on a 1954 235 truck engine.

I know that a vacuum advance on a passenger car 235 engine has a slightly different shape in comparison with the vacuum advance mechanism used on a truck - maybe the passenger car meechanism is mounted on the left side of the distributor? Does anyone have a photo of the passenger car vacuum advance on 54-62 235 engine?