Could be the twin-turbo Variation of the 13B engine created to electricity the 3rd-generation RX-7 launched in late 1991. Each rotor on 13B-REW has an individual combustion chamber volume of 654cc. With two rotors, the total displacement was 1308cc. Ideal in shape for just a Mazda swap or substitution undertaking. https://mazda13brewmotorforsale16936.amoblog.com/13b-engine-for-sale-an-overview-51685600