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TracTuff PRB/ PRC Filler Neck - V3


An inexpensive solution for all you K20A, K20A2, K20A3, K20Z1, and K24A1 engine owners looking to simplify your cooling system! Whether you have added a radiator that does not have a radiator cap bung or you are just in need of a higher fill point to aid in burping the sometimes troublesome k series cooling system, we've got you covered.

The filler neck starts with a beautifully machined 6061-T6 flange that incorporates the largest port possible within the OEM gaskets footprint, a 1/2" NPT water bypass port, and machined o-ring groove for the OEM gasket. You can choose to add a sensor port directly to the top of the flange (near the logo) or the side of the flange (under the outlet) as well as choose to have the outlet come out of either of the two ports; making the product universal for FWD and RWD applications... depending on you specific selection.

Outlet coming out the side (shown) would be typical for FWD applications but swapping the filler tube spot could also lend itself will to FWD applications as well as RWD applications. Just choose standard hose (1.25" OD) or -16 male flare outlet.

NOTE: Made to Order - Contact for ETA - If you are interested in a specific design that varies from this, please email us at The cap bung has a 1/16" NPT port for connection to an overflow and uses early model Honda radiator caps; such as an 88'-91' Civic/ CRX or 90'-93' Integra. If you are using AN lines, I 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 water bypass port and the hardware kit includes a 5/8" hose fitting, a plug, two stainless M6 socket head bolts, and a Genuine Honda gasket. The filler tube is welded so that it sits level when bolted to an engine leaned back 15° (OEM position) for the traditional option and leaned forward 8° (intake side) for the gangster lean mount option. 

DISCLAIMER: Configuration 1 may have clearance issues with throttle cable pulley and/ or fuel rail plumbing; you will need 4.00" of space directly in front of the cylinder head as measured from the water neck mounting surface. The centerline of the filler tube sits at approximately 3.00" and comes straight up and occupies a portion of the fuel rails inlet/ outlet path. I strongly recommend a center feed fuel rail so the driver side port can be plugged. Intake manifold injector placement and injector dimensions can improve or complicate the situation so I encourage you to communicate your situation or simply choose an alternative product such as V1 Filler Neck.

If you are using configuration 2 for a RWD layout; you will need at least 2.00" of clearance as measured from the cylinder heads M10 threaded boss to the firewall.