what does it mean when you use "作“ as a measure word for people? What does it mean when you use "作" as a measure word for people ? for example, in 沈从文‘s 《丈夫》 I read the line 都使这作丈夫的想起了村长同乡绅那些大人物的威风 

Is 作 different from 位？
It's not a measure word. It means act as; be.

作丈夫的 could be translated literally as The people who act as husband, or just The husband.