TracTuff RBC/ RBB Billet Water Neck Assembly w/ Fill Port

TracTuff RBC/ RBB Billet Water Neck Assembly w/ Fill Port


A fabricated version of our RBC/ RBB Billet Water Neck with a radiator fill point. The flange and radiator cap bung are CNC machined from US Milled 6061-T6 aluminum with the absolute largest port you can fit within the restrictions of the OEM gasket and a 1/2" NPT accessory port. The outlet maintains the OEM position unless otherwise requested.

All billet parts are CNC machined from US milled 6061 aluminum. The domestic cap bung has a 1/8" NPT port and the import version has a 1/16" NPT for connection to an overflow. The domestic version uses any early model (late 70's Chevy C10 Pickup w/ 454) cap and the import version uses early model Honda (88'-91' Civic/ CRX and 90'-93' Integra) cap. 

NOTE: Made to Order - Contact for ETA - If you are interested in a specific design that varies from this, please email us at If using AN lines we also recommend designing the upper radiator hose so that there is droop/ give so the engines movement and does not push/ pull on the radiator and fatigue any parts. The billet neck has a 1/2" NPT heater port and the hardware kit includes a 90° hose fitting and a plug in the event you don't plan on connecting a heater hose. The filler is welded so that it sits level when bolted to an engine leaned back 15° (exhaust side) for the traditional option and leaned forward 8° (intake side) for the gangster lean mount option.