distributor vacuum advance

I hear you about harbor frieght....almost always cheap china crap. Vc208 do you know the degree of advance on it? How do I recurve my distributor? I don't know very much about distributors just what they do. I was looking on rockauto.com but there's so many options i have no clue. I searched under a 78 dodge aspen since they had the factory Super six option but there's 4 options and non if them say the degree. :(