Question of the Week: What's your favorite sleeper performance car? | Hagerty Media
A sleeper car is one you wouldn't expect to leave a snarling exotic car in its wake at the stoplight or dragstrip. Following Teddy Roosevelt's mantra of speaking softly but carrying a big stick, they keep their impressive horsepower hidden until it's called upon. Many factory-produced cars fit the sleeper mold. https://www.hagerty.com/media/archived/qotw-whats-your-favorite-sleeper-car/
My favorite sleeper is my daily driver, a 1988 Pontiac Fiero with a breathed on 4.9 Cadillac V-8 and 4 speed automatic transmission with modified final drive ratio of 3.43. In the 60 foot Grand Prix this car has surprised many an unsuspecting Mustang and Corvette owner. The only external indicator of the modification is a Cadillac 4.9 Port Fuel Injection emblem on the back bumper. The stock exhaust tips were retained to complete the illusion of stock and with the big muffler installed it is remarkably stealthy and quiet at idle. My other favorite is a manual transmission equipped 1986 Fiero also with the Cadillac 4.9. These engines are run by OBD 1 computers and are amazingly easy to tune to modifications.