Ergo, what is actually happening by taping up the "radiator" for a short while is that airflow through the cooling system is being reduced and airflow beneath the car is being reduced. This is not CREATING DOWNFORCE (thus creating drag) it is actually REDUCING LIFT (reducing drag). Reduced lift = reduced drag; reduced turbulent airflow = reduced drag. Reduced drag = Old Ford Falcons with pretty bodywork and decals go faster.

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Greg, isn't the "downforce" a result of all factors? Not just the removal of internal and underbody drag/lift?

My thoughts would be that the resultant increasse in downforce was due to the removal of the lift quotient under the car AND the increase in surface area of the carefully angled grill...which now acts like a diveplane.

Also, and i wish I could find the souce, I read some figures about downforce and I was amazed at the positive numbers these cars produce. (As long as they aren't going backwards)

(It makes what the guys like Lorenzen and Petty did back in the 60s more impressive)