Yes, the timing is programmed in the PCM. But the PCM needs a signal from the optical cam position sensor in the Opti to know where the engine is rotationally (e.g. - TDC for each cylinder). If the Opti is not indexed correctly to the nose of the cam, the PCM will be getting incorrect info regarding the position of the engine as it rotates. There is no reliable "0" reference on the MSD timing adjustment to insure it is indexed correctly.

Which means??????

 

So A few questions then:
1) When I send this in to MSD will they return it to be with it set to "0" by default?

2) Would it be possible to rig up a pointer of some sort and use a timing light to make sure it is set to "0"

3) What if I turned the set screw all the way in and then back it al the way out and counted the turns then divided by 2 and then re-inserted the set screw to the difference wouldn't that theoretically set timing to "0" since it goes +/- 5 degrees?

Thanx in advance for your help everyone.

 

You'll have to ask MSD for the answers to questions #1 and #3. Only they would know.

You could use a keyed damper with degree graduations on it, and add a pointer, set where you have verified the engine is at TDC #1 on the compression stroke. I have mine set up that way.

Or you could just by a GM Opti.