Quote Originally Posted by nos4blood70 View Post
Actually my car runs perfectly fine without it. Right at 180*. My front end seems a bit more floaty without it at speeds above 65 MPH. But this could be because my car is a Bonneville. H-body are different design than W-body. But then again I could be wrong.
Maybe it is the difference in design. I have seen a couple of posts saying the engine runs hotter without the deflector. Maybe different car relies differently on those deflectors. Anyway, as long as it does not overheat, I guess it is OK.

I remember I also read somewhere that those air dam help reduce the amount of air going through the underside and direct the air flowing more through the upper. This will help the traction and stabilize the car. I am not sure how significant it is. It is hard to believe but it might be actually true. I remember I once watched a F1 race on TV. The spoiler of one car fly off and the car immediately lost traction. I can never imagine the importance of such a small piece if I did not see it.