May be the twin-turbo Variation from the 13B engine intended to electric power the third-generation RX-7 released in late 1991. Just about every rotor on 13B-REW has one combustion chamber quantity of 654cc. With two rotors, the full displacement was 1308cc. Fantastic match for your Mazda swap or substitution job. https://edwinznbmr.blazingblog.com/29854568/about-mazda-13b-motor-for-sale