Briggs & Stratton 49R977-0033-Z1 Vertical Electric Vanguard Series EngineBriggs & Stratton 49R977 0033 Z1 Vertical Electric Vanguard Series Engine At an optimum 810cc, these commercial grade engines establish a new standard for zero turn engine displacement. For turf professionals, that means higher performing, more efficient, more powerful and, ultimately, more profitable commercial cutting.