A black 1968 Pontiac Firebird 400 HO convertible is the spark behind this question: what were you driving the first time you hit 120 mph? Pontiac’s 400 HO packed 335 horsepower and ran 0-60 in 5.3 seconds, quick enough to beat a 390 Mustang, a Camaro SS 396, and a 340 Barracuda in a 1968 Car and Driver test. Decades before traction control and ABS, that kind of speed took real nerve. Tell us your car, your engine, and the moment you found out what both were made of.