Chris (et al),
     
     I did an inline fan conversion on my bay-window. It was a panel
     van so it didn't have a rear heat outlet. 
     
     I have a FIAT X1/9 and they have a pretty powerful fan used to
     cool the carb. in hot weather. So I got a spare fan from a scrapyard
     and hooked it up to the tube that goes into the heater exchanger tubes
     in the engine. I then went to the cab to feel how much air was comming 
     out. It was about the same as before :( 
     
     So I figured that the fan shouldn't be at the back coz the pressure
     drop along the pipe(s) result in zero pressure at the cab. So I hooked
     the fan up to just below the vertical steel pipe that you can see in
     the cab. The results were good, with the air actually BLOWING out of 
     the screen vents. I do feel that a more powerful fan would be more
     ideal, as even with this setup the van didn't get any warmer. It just
     meant that you could flick a switch and demist the windsheild alot
     quicker. So basically I installed the fan under the cab floor and as
     such it would suck the hot (warm!) air from the rear where it was
     being pumped forward by the engine.
     
     The FIAT fan lends itself to the conversion as it is the correct 
     shape. It looks something like this:
     
              _____
             |     |_===  / motor
     in  --> |     |_   |
             |_____| ===
              \    |_
               \_____|  -----> out
     
     
     I just cut the large flexible hose that goes to the cab tube and
     inserted the fan, then bolted it to the cab floor, underneath.
     
     Again the results are not dramatic, and it still depends on the
     condition/quality of your heater boxes and tubes.
     
     I'll follow this article up with my next idea - water boxes!!
     
     Lee.
     
     Cold '64 Samba
     L.S.Griffiths@Physics.Salford.ac.uk
     http://146.87.136.48/