What kind of engine is interchangeable in your 1989 Mazda RX7 body?

The 1989 Mazda RX-7 is primarily designed for the Wankel rotary engine, specifically the 13B model. However, some enthusiasts have successfully swapped in other rotary variants, like the 13B Turbo or even the 20B, which offers three rotors for increased power. While traditional piston engines can be fitted with significant modification, such swaps are less common and typically involve extensive custom work.