General Motors bought out Holden in 1931, and introduced the Vauxhall Wyvern in 1938 based on the British Vauxhall H-series but with a chassis for the rough roads. From 1948 to 1951 Holden produced its own version of the Vauxhall L-series, again with chassis, and with altered sedan or convertible Caleche convertible. The next Wyvern was based on the Vauxhall E-series, built as a monocoque sedan and as a convertible or coupe utility both with chassis. The first Holden badged car was introduced in 1949, actually a design already rejected by Chevrolet. However, assembly of British Vauxhalls continued alongside Holdens until 1965 when Australian regulations encouraged local content. After that, Opel and Vauxhall designs were often adapted to become Holdens.