172 cup heater query

[ashley_t]

main question...

I have removed the aircon bulkhead unit on my 172 and im fitting a fan unit from a cup. What i want to know is what does the cup have covering the bulkhead hole shown

No hole at all? Spot welded plate?

Secondly... is there an actual difference between a heater box from a climate control car and a cup? I know the cup has mechanical heater controls but is that interchangable or will i have to fit the cup heater box aswell

 

[Pauleds]

That hole is blanked off on cups.
Think heater boxes are different too with 2 cables going from the control unit to the side of the heater box

 

[ashley_t]

Bit of sheet metal tacked in place and sealed then

Sounds like im fitting the heater box from the cup aswell... joy