The 1964 Pontiac GTO convertible, often considered the first true muscle car, was a 389 CID V8-powered, 2-door cruiser that launched a performance revolution. It featured a 325-348 hp engine, optional Tri-Power carbs, a 4-speed manual or 3-speed auto transmission, and distinct twin hood scoops, with 32,450 units produced, of which 7,384 were convertibles.