Expanding on (and making slight corrections to

) what Layla's Keeper just said:
Tempest was the only one to use the rear-mounted transaxles. It shared them with the Chevrolet Corvair: like the II/Nova it was another "remote cousin" (the Corvair was in-and-of-itself
extremely unique, possessing a rear-mounted all-aluminum air-cooled Boxer-6). F-85 and Special used regular longitudinal transmissions and solid axles.
Tempest also used the largest displacement four-cylinder engine (that I know of, anyway) in a production car: 3188cc (3.2L). It was basically a Pontiac 389 (6.5L) V8 cut in half.
F-85 had a model, introduced in 1962, called
Jetfire. It used the very first application of a turbocharger to a production car engine. Corvair's Boxer-6 was eventually turbocharged as well, released shortly after the Jetfire (unlike the Jetfire, which required an alcohol fuel additive to prevent detonation, the Corvair used a regular ol' turbocharger).
The Special was the first American car to use a V6: a distant relative of the modern day "3800" V6.
[/nitpick]