Aerodynamics & Diverting Wind Resistance ?

pauly said
I’d put a piece of cardboard over the radiator first just to try it out. Run it up the road a few times. If it gets hot quickly, it may be too much. Used to see people do it up here in the winter to try to keep the engines warmer.

some of us still do it in the winter up here... maybe we put a 6" hole in the center for cooling, but some cars won't heat up without it.