The fuel rail ports are tapped for 8AN ORB

The plumbing kit includes the items shown in the image and allows easy hookup to the factory feed line. It is intended to be used with the factory pressure regulator, but can also work with an aftermarket regulator.

Appropriate fittings must be selected based on the specific application. Ample space around the fuel rail port(s) is necessary for larger accessories such as fuel pressure regulators, fuel pressure gauges, and fuel pulse dampers. To verify clearance, the dimensional drawings on the product pages can be used as a reference guide.

However, there are likely many other variations that are compatible. And even though the Radium Engineering fuel rail has 3 fuel rail mounts, it will work on many of the 2-bolt intake manifolds, as shown below.

Manufactured with a large internal bore, the fuel rail can support all necessary engine power requirements. They are CNC machined from 6061 aluminum, anodized, and laser etched for a high quality surface finish. Like the OEM fuel rails, the injector bores are 11mm ID so factory injectors, or any equivalent aftermarket injector, can be used. 

The fuel rail is compatible with all fuel types including popular alcohol mixtures such as E85. The OEM spacers are required for mounting the fuel rail.