Distribator off by one tooth - Pulley casting number

[40cpe]

Your distributor rotates clockwise, so picture #4 shows the rotor past (ATDC) #1 and the reason it doesn't run well set on the button. You rotated the drive gear CCW which put the rotor at before the #1 (BTDC). What you aren't showing here is that you rotated the distributor housing (and the distributor cap) counter clockwise to time the engine. This put the #1 terminal back in the same relation with the rotor as before the gear change. If the timing light pick-up is on #1 plug wire it can't pick up signals from #2 or #5 terminals on the cap. I have changed positions of the drive gear in order to get clearance on the vacuum can to adjust the timing but I always have to rotate the distributor body to compensate. It never changes the location of the TDC mark on the pulley.