Ya the CC blower is plastic. I thought it was aluminum when I bought it, but its not. I saw an explanation and its only meant to run air over a Castle 2200 motor which is already finned. All the black plastic does is keep the fan in place above the motor. I would guess you are going to retain heat with the plastic shroud.
If you have a smooth can motor the CC blower isnt going to do much. I tested an 80mm fan over a smooth can feigao and it really didnt do much. Linc's idea is good. An aluminum heatsink will do best. I have tested and tested trying to keep my feigao motor temps down and that works the best for me. If you want the extra cooling then a fan or two on that and it will work wonders. During winter all I need is the heatsink by itself. During summer I need the heatsink and fans.
http://www.rc-monster.com/proddetail.php?prod=RCM01
Here is a link for what you should be looking for. This will work wonders on temps as long as you have a little air flow over them.
If you look at my avatar, that was my pathetic attempt to keep my feigao cool with an 80mm fan.