The Pegaso Z-403 Monocasco, was a two-level monocoque (chassisless) coach, fitted with a 125-hp diesel engine asymmetrically mounted amidships, and built in Spain by Enasa between 1951 and 1957. First Z-403 body design date back to 1949. It brought notable contributions to the passenger service for its safety and comfort and was considered an «auto-pullman» by virtue of its great comfort and its amenities. In the standard version it was equipped with radio, bar and a small bookcase.