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Alignment can be also be done on the bench using an old cap with holes drilled in it. Line up the reluctor with the pickup and look thru the spark plug wire hole to see if the alignment is correct
Or align rotor with spark plug hole, remove cap and check reluctor to pick up alignment

The vac adv plays an important part in where the "zero" position of the pickup ends up. Many times shimming the vac adv away from the housing quickly corrects any offset. You can also shorten the length of the arm on the vac adv as well if you are creative enough. Typically you will need to space the canister away from the dist body or shorten the arm length to correct any misalignments.

Again I will emphasize how much better any car runs with a phased distributor.

The pic shows the typical misalignment



let me ask- this picture shows a misalignment at idle. but, when the distributor starts advancing, the pickup will move counterclockwise and brign the misalignment back into alignment, won't it? so the net effect would be proper rotor phasing at higher rpm where its more important.



Once the rotor/terminal & reluctor tooth/pickup is phased it is not affected by mechanical or initial changes. The relationship between the relutctor and rotor is fixed and the position of the pickup to the terminal is fixed also. Only when the vacuum advance comes in will it go out of whack because the pickup now moved in relation to the cap terminal.

If your not running vac advance just shoot for dead on but with vacuum advance perhaps you want to adjust it so that the rotor is equidistant from the terminal a zero vacuum to max advance????

i dont believe thats true. i believe mechanical advance as well as the initial timing will change the orientation pickup /cap terminal to the rotor/reluctor spline

the relationship of the rotor tip and star wheel is fixed to the distrib shaft and is driven by the cam (but the relationship can be adjusted as stated above).

The cap terminal is fixed to the body of the distrib housing and will be moved back and forth as the housing is twisted CW or CCW.

When the housing is twisted CW or CCW, the pickup moved forward or aft of the reluctor. thats how mech timing is adjusted. Move housing so the pickup moved toward the reluctor spline and the coil fires off earlier thereby advancing it. move it away, the timing is retarded.

When the coil fires it sends the pulse down to the rotor to arc out to a plug terminal. it WILL JUMP A GAP here. the question is how much.

as the centrifigal advance kicks in, the rotor and the reluctor move so that the reluctor spline moves towards the pickup thereby advancing it

Now, i would imagine the width of the conductor on the tip of the rotor is such that one corner of it aligns with the front edge of the 1/4 wide contact on the cap and as the engine advances, the rotor contact swings through the terminal contact.

point is, the mech and the vac advance changes the relationship of the reluctor spline to the pickup. since the reluctor spline is tied to the rotor it will move in relation to the housing annd the cap terminal is tied to the housing.

Unless the setup was so far out of whack that the rotor tip was so far infront of the cap terminal or already behind it such that the spark couldnt jump (or would jump to the next terminal), you'd never see a problem.

Im going to play with my distributor and see what the alignment is like at my intial timing (18 deg) and compare it to a stock (4 degrees adv) and see the alignment