Need help NON mopar 1967 Pontiac Lemans 326

Vacuum source =manifold vacuum.
Yes,you should be able to move distributor one tooth. But only clockwise. So you have to go all the way around. Hard to explain,turn while lifting and drop into next tooth. Repeat until its where you want it. It will slip past the gear and still barely grab the water pump. Done it 100’s of times.