Turning the distributor on a Vortec does NOT change the timing.
It changes the alignment of the cam sensor and the crank sensor, so the computer "knows" which cylinder is firing; and it changes the alignment between the rotor tip and the distributor cap terminal, so the spark doesn't jump to the wrong terminal.
Has NOTHING to do with ignition timing otherwise. Base (initial) timing is handled by the CRANK sensor, changing the distributor position doesn't change the crank sensor location.
Ideally, the cam sensor alignment should be within 2 degrees.
This has been on my mind re pending inlet manifold gasket change.
To be clear here, the cam sensor is on the cam - yes?
And the orientation of the distributor is only important for connecting the rotor tip to the appropriate terminal inside the cap - yes?
So, If i mark the body of the distributor to some reference point and re-fit in exactly the same position there shouldn't be a problem. But what's vexing me is that the skew gear will rotate the distributor shaft during removal and on refitting it will have to re-engage with the exact same tooth on the cam - how is this achieved? If the shaft rotates at all within the distributor when it is removed that orientation will be lost. Locking it to the distributor before distributor removal will then lose the distributor body position.
How do you guys deal with this?
NB, I don't have a scanner so have get this right manually.