Oldsmobile Toronado GT
The Toronado GT was a special package for Oldsmobile’s personal luxury cruiser. The car was available for a few short years ending in 1970. From the outside, the Toronado GT looked like an ordinary Oldsmobile, and the same 455 engine powered it, but the difference was the details (via Hemmings).

The GT package upped the power to a magical 400 HP, added various suspension upgrades, bigger and stronger front disc brakes, and better interior equipment. The GT was a rare option, and people seldom decided to order Oldsmobiles with this package. That is precisely why nobody knows about it today.