Mil-spec Tucked 13B Harness (FD3S/Rx7) This wire harness is made specific for a RX7 FD3 Chassis, not intended to be used for a 13b standalone engine harness. For "Right hand drive" customers, the ECU type will be for the earlier model (Our harness does not support the Austrailian 16-bit ECU's from 96-98) rx7 fc engine | eBay Find great deals on eBay for rx7 fc engine. Shop with confidence. Skip to main content. eBay Logo: Shop by category. Mazda rx7 13b turbo II engine harness wiring loom FC M/T rotary fc s4 s5 rx-7 (Fits: RX-7) Pre-Owned. $300. Buy It Now +$20 shipping. 12 Watching. Watch.