LA small block timing is suddenly way off

-A circle has 360*. If you divide the circle into 8 equal parts, each part would be 45*. So if the rotor was 30* past the no 1 tower, then the ignition system might be firing into the next tower past the true #1 at full advance or it wouldnt run at all. .

Cam is at 1/2 crank speed,, so 30* at the crank is only 15* at the rotor,, hence, - rotor is still 30* from the next tower.. ( 60* at the crank )

hope it helps