[Bishop92T]

N/A and turbo heads are the same. There are two known different 7m heads, early and late. The difference you can see by looking into the intake runners.

 

[Bishop92T]

Hrm, couldn't find the old picture I took of the differences so I'll just have to post this pic:

Early style is on top, the divider comes much closer to the edge of the head and is a bit thinner. On the later style the divider sits very far back and is thicker.