Traveling over the Smoky Mountains in a '63 with camping
rig and, on a downhill, we managed to pass somebody.  Wow!

Then we were passed by a ?'66 like we were standing still.
The speed was not as impressive as the cornering ability.

Caught him some miles later at a roadside attraction and,
when my Dad asked how he did that, he showed us a half-ton
of firebrick on the floor.  His center of gravity must have
been just above the axle...

--dan