Know you have me confused about how the plate could effect Vacuum Adv ?
The springs and weights alter the rotor movement .
The vacuum can move the reluctor plate.
They are 2 seperate parts
I'll try to explain. If this is wrong then someone can delete this.
If we have 2 plates one with short slots and one with long slots. In both cases we want 34 deg at wide open throttle for best power.
Long slot = 10 deg at Idle and 34 deg wide open.
Short slot = 20 deg at idle and 34deg. wide open.
Long slot (10 deg)+ vac adv (?) = just right amount of timing at cruise rpm.
Short slot (20 deg) + vac adv (?) = too much timing at cruise rpm.
? represents the amount of timing your vac. adv. adds.
