The fuel rail ports are tapped for 6AN ORB and 8AN ORB.

COMPATIBILITY
2021+ Toyota GR Yaris
2023+ Toyota GR Corolla

-Anodized surface finish for wear and corrosion resistance
-Lighweight aluminum construction
-Inner bore diameter: 0.6 inch
-Compatible with aftermarket Bosch EV14 fuel injectors
-Can be converted to a pressure regulated return system
-No special tools required for installation
-Fits under the factory engine cover

Manufactured with 0.6" large internal bores, the Radium Engineering fuel rails can support all necessary engine power requirements. The 2 end ports are 3/4"-16 threaded (8AN ORB). The upper area of the engine is very narrow so the 2 top ports are 9/16"-18 threaded (6AN ORB)

Stainless steel mounting tabs (shown) are included for superior strength. 

The OEM fuel injectors are compatible with these fuel rails. The machined ports are compatible with 11mm upper injector O-rings, as shown below. Because of the tight clearance, the injector electrical connector can be tricky for aftermarket injectors.

When used in conjunction witht he 20-0766 fuel rail, the 20-0766-PK add-on plumbing kit permits a plug and play connection to the factory G16E-GTS fuel system.