421-02-06-BLK 1/8" NPT to 3/8" Hose Tail - Black

Speedflow SF421-02-06-BLK | 1/8" NPT to 3/8" Hose Tail | Black | 421 Series

The Speedflow SF421-02-06-BLK is a precision-machined 1/8" NPT male to 3/8" hose tail adapter in black anodised finish, part of the Speedflow 421 series NPT hose tail range. This stepped adapter connects 1/8" NPT ported components to the larger 3/8" (approx. 10mm) rubber or silicone push-on hose — ideal for oil pressure, coolant, and breather line applications where a step-up in hose diameter is required for improved flow or routing flexibility.

Product Specifications

• Part Number: SF421-02-06-BLK
• NPT End: 1/8" NPT male
• Hose Tail: 3/8" (approx. 10mm) barb
• Finish: Black anodised
• Series: Speedflow 421 — NPT Hose Tails (Aluminium Barb Fittings)
• Compatible With: 1/8" NPT female ports and 3/8" ID rubber or silicone hose

Applications

The SF421-02-06-BLK is a versatile stepped hose tail adapter suited to a range of performance plumbing applications, including:

• Oil pressure sender and gauge line connections stepping up to 3/8" hose
• Coolant temperature sender and bypass line connections from 1/8" NPT ports
• Turbo oil feed line connections from 1/8" NPT ported centre sections
• Engine block and head coolant port connections stepping up to larger hose
• Breather and catch can line connections from 1/8" NPT ported components
• Any application requiring a 1/8" NPT male to 3/8" push-on hose step-up interface

1/8" NPT Step-Up — Why Go Larger?

The 1/8" NPT port is common across oil pressure senders, turbo centre sections, and small coolant ports. While a matched 1/8" hose tail is sufficient for low-flow gauge and sensor lines, stepping up to a 3/8" hose tail is beneficial when routing to a larger hose section, reducing flow restriction in oil or coolant feeds, or when 3/8" hose is the standard used throughout the rest of the build for consistency. The SF421-02-06-BLK provides this step-up in a single compact fitting.

NPT Installation Note

NPT fittings use a tapered thread that seals via thread interference. Always apply appropriate thread sealant or PTFE tape to the NPT male threads during installation. Do not overtighten. Secure the hose tail with an appropriate hose clamp for pressurised applications.

Sold individually. Compatible with 1/8" NPT female ports and 3/8" ID rubber or silicone hose.