421-04-05-BLK 1/4" NPT to 5/16" Hose Tail - Black

Speedflow SF421-04-05-BLK | 1/4" NPT to 5/16" Hose Tail | Black | 421 Series

The Speedflow SF421-04-05-BLK is a precision-machined 1/4" NPT male to 5/16" hose tail adapter in black anodised finish, part of the Speedflow 421 series NPT hose tail range. Connecting 1/4" NPT ported components to standard 5/16" (approx. 8mm) rubber or silicone push-on hose, this adapter is a matched-flow fitting ideal for oil pressure feeds, turbo oil lines, fuel connections, and sensor line builds where the 1/4" NPT port steps to a compact 5/16" hose run.

Product Specifications

• Part Number: SF421-04-05-BLK
• NPT End: 1/4" NPT male
• Hose Tail: 5/16" (approx. 8mm) barb
• Finish: Black anodised
• Series: Speedflow 421 — NPT Hose Tails (Aluminium Barb Fittings)
• Compatible With: 1/4" NPT female ports and 5/16" ID rubber or silicone hose

Applications

The SF421-04-05-BLK is a versatile adapter suited to a wide range of performance plumbing applications, including:

• Oil pressure sender and gauge line connections from 1/4" NPT ported blocks and sandwich plates
• Turbo oil feed line connections from 1/4" NPT ported centre sections
• Fuel pressure gauge and regulator line connections
• Coolant temperature sender and bypass line connections
• Vacuum and boost reference line connections from 1/4" NPT ported components
• Any application requiring a 1/4" NPT male to 5/16" push-on hose interface

421 Series 1/4" NPT Hose Tail Range — Choosing the Right Size

The Speedflow 421 series offers multiple hose tail sizes for the 1/4" NPT port, allowing you to match the hose tail to your specific hose ID and flow requirements:

• SF421-04-05-BLK — 5/16" hose tail: suits oil pressure feeds, turbo oil lines, and sensor connections (this listing)
• SF421-04-06-BLK — 3/8" hose tail: for higher-flow applications or where 3/8" hose is the build standard

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 1/4" NPT female ports and 5/16" ID rubber or silicone hose.