DeTomaso Mailing List: December 2000, Message #59

Forget about cutting from inside the car; to get any sort of airflow, you 
need at least a 2-1/2" dia hole, which will require a 1/2" drill motor. This 
is just too big to manipulate under the dash. From outside, afer VERY careful 
measurements, you can hole-saw thru the area covered by the wiper grilles. I 
used 90 degree sweat-solder fittings driven onto aluminum tube extensions 
made with a lip on top. The 90 degree fittings direct the air at your body 
rather than at the floor. The lip, sealed with RTV, makes a riser that keeps 
water from running in, and I found that Coke cans with big slots in the 
sides, fit right on top of the auminum tubes to serve as baffles against 
airborne water.  Fabricate a throttle valve for the 90 degree fittings so 
airflow can be turned off when its cold, and you're done.  There isn't much 
room under there, so be sure you know where you want them, but the rest is 
fairly easy and was the subject of a POCA article some years ago. Good luck- 
J DeRyke