E.B a correction to my comments re the class system for the RX7
The total homologated capacity for the 13B ( see the FIA homologated Madza Cosmo CD23C i.e. the RX-5) is 1308 c.c for the 2 rotors. The FIA mandated an equivalency total capacity of 2616 c.c. The FIA homologated the Group 1 and Group A Mazda RX-7 SA22C with only the 12A engine. The capacities being total capacity of 1146 c.c for the 2 rotors and an equivalent capacity of 2292 c.c.
CAMS in Australia homologated the 13B peripheral port engine for the SA22C RX-7 in 1981 and mandated an equivalent capacity of 4584 c.c.
Some videos of my RX7 dynotune prior to the Phillip Island Classic doing 9,000 rpm
https://www.youtube.com/watch?v=d0Aa_gue-Vc
https://www.youtube.com/watch?v=u4JiioR4ghQ