Still going to get a complete Distributor but a new issue that sounds Ignition related.
Daughter says car runs fine but every once in a while she gets a total "miss" and then car is fine.
Just looked under the hood to make sure the Ignition wires are in the Cap nicely and noticed that the Coil itself rattles around within it's Core/ Bracket. I wonder if this sloppiness is throwing off the high voltage to the Ignition Cap.
Any thoughts?

 

dunno if that is the issue...friend of mine had the same shake issue,,,he used small pieces of thin sheet metal to slide between coil and metal holder it did stop the shake....look for visual cracks(white lines) and ohm it...follow attached pdf...remember to subtract the ohm resistance of the leads from the primary ohms to get the total....EX: @200 ohms.....leads together = 1.0, leads on primary coil = .9.... 1.0 - .9 = 0.1 ohms..

 

The core is loose on one of my vehicles and it seems to run great. Does not have and detonation or misfires. That doesn't mean it could be a problem though. I have wondered the same thing but never looked into it.
The core (surrounding metal frame) is there to channel the magnetic field created by the primary winding into the secondary winding. The core should also have a good ground. This is the part I learned this morning. This is necessary to prevent stray voltage from forming in the core and causing damage to the transformer (ignition coil) windings.
Overall testing of the windings would work but that is only going to indicate complete or major failure. If you are sure the ignition coil is the problem but are not sure I hope this helped. It sure makes me suspect of mine since I did not know the importance of grounding. I have removed mine several times and did not give much attention when I put it back on.

 

If you are talking about the plastic primary & secondary winding being loose in the outer laminated steel core, I wouldn't worry too much about it. The coil will be most efficient with uniform air gaps between the windings & the core, but minor movement will not cause any problems.

About the only thing that could happen is wear on the overmold of the primary/secondary windings which could eventually lead to a short. Shimming as jkyle187 suggested would eliminate this concern.