Ok got on the roots /screw deal. i guess in my mind a high helix roots like the one shown by Outlawd is just moving air as described by Poly. Just because it is being screwed to the rear does not make it a screw compressor.
Anyway, I guess I will just call a blower company as suggested, and ask about doing what I want to do here. I have an internal struggle with this. On one hand, seems to me that the blower rotors may need more clearance in this application with no liquid for cooling. On the other hand, I know that more clearance creates heat.