[BR3W CITY]

Little known fact, the cupholder that comes on the back of the glove box door (at least on my 66) is in fact the BEST cupholder on the planet.

I don't know why or how, but the little 1/8th inch crease that the cup sits in holds it like nothing else. I've put a big AZ Ice Tea (the tall cans) in there, and took off from a stop, kicking the rear out slightly. That cupholder held that awkward tea can up to 60, and didn't blink until I applied the brakes hard, rocking it forward but not spilling it over.
Explain that to me with physics....that little excuse for a cupholder shouldn't work.