Out of stock
SKU: HLYFB402
UPC: 090127740156
MPN: FB402
The Holley radiator hose fitting 1.75in to 16an ORB is a precision adapter designed for custom cooling system plumbing in high-performance automotive applications. This straight-port fitting bridges two common industry standards—1.75-inch barbed hose connections and 16 AN (eight-sixteenths) O-ring boss ports—making it essential for builders upgrading radiator systems, engine swaps, or performance cooling setups. Whether you're fabricating a street rod, restoring a classic engine bay, or assembling a competition cooling loop, this adapter ensures secure, leak-free connections between incompatible component sizes.
Manufactured from aluminum and finished in natural (uncoated) form, the FB402 features a robust O-ring sealed design that prevents coolant weeping under pressure and thermal cycling stress. The 16 AN O-ring boss male threads accept standard O-ring face seal fittings with positive mechanical engagement, while the 1.75-inch barbed end securely grips reinforced radiator hose using a standard worm-drive or band clamp. Aluminum construction provides excellent thermal conductivity and corrosion resistance in glycol-based coolant environments, while the straight configuration minimizes flow restriction and simplifies tight engine bay routing. This fitting's compact footprint (3 x 2.1 x 3.1 inches) and light weight (0.3 lbs) make it ideal for space-constrained installations.
Professional engine builders and cooling system fabricators choose the Holley radiator hose fitting 1.75in to 16an ORB when connecting aftermarket radiators, water pump outlets, or bypass blocks that use AN fittings to OEM or custom hoses. The O-ring boss interface is compatible with any standard 16 AN male fitting, offering flexibility across multiple cooling component brands. Installation requires hand-tightening the male fitting into the radiator or block's ORB port, then securing the hose to the barbed end with a properly sized hose clamp—no special tools needed. This adapter is sold individually, allowing builders to purchase only the quantities required for their specific plumbing layout.
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