Good memory, Phil. The Car & Driver article states that the Pinto's grille,
fully blocked netted a
2.6% increase in MPG at 70 mph.
The interesting part was:
when combined with their giant air dam, the full grill block resulted in a
13% increase in MPG @ 70 mph.
With the area ahead of the radiator opened up, but the sides remaining covered, the MPG advantage was
9%.
Goes to show how aero changes are not isolated. Change the flow in one area, and it has downstream (and upstream, if done at the rear of the vehicle) consequences.
