Distributor"clocking" refers to the relationship between the position the rotor points to the position of the slot at the bottom of the distributor shaft. Not all aftermarket distributors are "clocked" like the original. So, you could end up with the rotor pointing a different direction. Someone posted a picture showing the difference.
Oh, that makes since. Is that easy to do? Do I just clock the new dizzy to match the old one by turning the shaft to match the relation to the #1/rotor position on the old one or something?