SBC Fuel Pump Fittings: Your Complete Guide to Leak-Free Performance

Selecting and installing the correct SBC fuel pump fittings is absolutely critical to achieving a reliable, leak-free, high-performance fuel system for your Small Block Chevy engine. Overlooking these seemingly small components leads directly to frustrating fuel leaks, dangerous fire risks, vapor lock, reduced engine power, and expensive pump failures. This comprehensive guide provides clear, practical information to help you confidently choose, install, and maintain the right fittings for your specific SBC fuel pump setup – whether stock replacement, high-pressure EFI, or carbureted performance applications.

(SBC = Small Block Chevy)

Why Fuel Pump Fittings Matter More Than You Think

Fuel pump fittings are the critical connections joining the fuel pump to the hard lines and flexible hoses feeding your engine. They seem simple, but their role is vital. Fittings ensure a high-integrity seal under significant pressure, preventing dangerous fuel leaks. They guide the fuel path efficiently, reducing restrictions that starve the engine of fuel during acceleration or high RPM. They maintain consistent fuel pressure, essential for carburetor jetting or EFI injector pulse accuracy. They prevent air infiltration into the system, which causes vapor lock and hard starting. Poor quality, incorrect size, or damaged fittings are leading causes of fuel system problems in SBC builds. Choosing the right fitting isn't an afterthought; it's fundamental to system safety, performance, and longevity.

Know Your SBC Fuel Pump Outlet Threads: The Starting Point

The journey to the right fitting begins with identifying the pump outlet thread size and type. This is non-negotiable. Installing a fitting designed for the wrong thread will, at best, fail to seal and leak; at worst, it can damage the pump outlet port threads beyond repair.

  1. Carbureted Stock Replacement Pumps: The most common outlet thread is 1/4" NPT (National Pipe Taper). This is a tapered pipe thread standard. Many aftermarket mechanical and electric pumps designed as replacements use this size. Important: Confirm the thread size for your specific pump using its specifications sheet or physically measuring. Other sizes like 3/8" NPT occasionally appear but are less common for carbureted pumps.
  2. Carbureted High-Performance Pumps: Pumps delivering higher flow rates (e.g., for modified engines or larger carburetors) often use a larger outlet thread. 3/8" NPT is prevalent here to support the increased fuel volume and reduce restriction.
  3. EFI Fuel Pumps: Electronic Fuel Injection systems operate at much higher pressures (typically 40-70+ PSI) than carbureted systems (4-10 PSI). EFI pump outlets require threads compatible with high-pressure fittings. Common standards include:
    • M16x1.5: A very common metric thread on many aftermarket EFI pumps. Requires specific fittings.
    • AN-6 ORB: ORB (O-Ring Boss) ports with an O-ring sealing surface and an AN-6 sized thread (typically 9/16"-18). Requires an ORB to AN adapter fitting or a hose end designed for ORB.
    • AN-8 ORB: ORB (O-Ring Boss) ports with an O-ring sealing surface and an AN-8 sized thread (typically 3/4"-16). Less common on SBC pumps than M16 or AN-6 ORB.
    • NPT: While less common on high-end EFI pumps due to inferior sealing at high pressures, some budget or universal EFI pumps may still use 1/4" or 3/8" NPT outlets. Exercise extreme caution using NPT threads at EFI pressures due to vibration leakage risks.
  4. Mechanical vs. Electric Pump Ports: Electric pumps can mount anywhere (in-tank or inline), while mechanical pumps mount directly to the engine block. The port type (NPT, ORB, M16) depends on the pump design, not the power source. Always verify the thread on your actual pump.
  5. Confirmation: Never assume. Consult the manufacturer's documentation for your specific fuel pump model. If unavailable, carefully measure the diameter and thread pitch using calipers and a thread gauge before purchasing any fitting.

Understanding Fitting Types: Straight, Elbow, Adapters

Fittings come in various configurations to meet the routing needs of your engine bay. Choosing the right style minimizes stress on lines and improves packaging.

  1. Straight Fittings: Provide a direct, in-line connection. Ideal when the outlet points directly where your fuel line needs to go, minimizing bends. Offers the least restriction. Common in NPT (e.g., a simple brass nipple) and AN configurations (e.g., a straight AN hose end).
  2. Elbow Fittings (90 Degree / 45 Degree): Change the direction of the fuel line immediately at the pump outlet. Crucial when space is tight or the outlet direction isn't ideal for the required fuel line routing. They significantly reduce the need for sharp hose bends which can kink and restrict flow. Common angles are 90° and 45°. Available in NPT, ORB, AN, and metric threaded versions.
  3. 45° vs 90° Elbows: A 45-degree elbow creates a gentler change in direction than a 90-degree elbow. This offers slightly less flow restriction and reduced turbulence. However, a 90-degree elbow is more compact when space is extremely limited. Choose based on available space and desired flow efficiency. For EFI systems, minimizing turbulent areas helps maintain stable pressure.
  4. Banjo Fittings: Less common on SBC fuel pump outlets themselves, but sometimes found on specific pumps or at other points in the system (like near hard lines on the frame). They use a bolt passing through a hollow, ring-shaped connector and seal with copper washers on both sides. They allow rotation for line positioning after tightening but can have slightly higher flow restriction compared to straight-through designs.
  5. Adapter Fittings: The essential translators of the fuel system world. When your pump outlet thread doesn't match the thread type or size you need for your hose end or next component, an adapter provides the bridge. Examples:
    • NPT to AN: Connects a pump with an NPT outlet to an AN-style hose end. Very common conversion.
    • M16x1.5 to AN: Adapts the common EFI pump metric thread to AN standard.
    • ORB to AN: Adapts O-Ring Boss ports to AN hose ends. Can be male ORB to male AN, female ORB to male AN, etc.
    • 3/8" NPT to 1/2" NPT: Increases or decreases pipe thread size.
    • Swivel Adapters: Often used when connecting braided stainless hose to rigid components. A nut holds the hose end assembly, while the stem (which threads into the pump) can swivel independently. This greatly simplifies final positioning and tightening without twisting the entire hose assembly. Highly recommended for ease of installation and reduced stress on the hose.

Material Matters: Brass, Steel, Aluminum

The material of your fuel pump fittings impacts corrosion resistance, strength, cost, and compatibility.

  1. Brass Fittings:
    • Pros: Excellent corrosion resistance, particularly good with gasoline. Easy to install due to softness. Threads seal easily. Cost-effective. Widely available for NPT applications. Good electrical conductivity (relevant for static dissipation on some lines).
    • Cons: Lower tensile strength compared to steel. Not suitable for high-pressure EFI applications where pressures exceed 60-70 PSI consistently or where extreme vibration exists. Threads can be damaged during overtightening.
    • Best Use: Ideal for low-pressure carbureted fuel systems. Acceptable for lower-pressure EFI return lines if within pressure rating. Common for basic stock replacements.
  2. Steel Fittings (Carbon Steel, Zinc Plated Steel, Stainless Steel):
    • Carbon Steel w/ Zinc Plating: Offers higher strength than brass. Plating provides moderate corrosion resistance. Common in OEM and lower-cost applications. Can still rust over time, especially in salty environments. Check pressure ratings carefully.
    • Stainless Steel (304 or 316):
      • Pros: Superior corrosion resistance – practically impervious to gasoline and road salts. Excellent high strength, suitable for very high-pressure EFI systems. Withstands extreme vibration environments better than brass or plated steel. Aesthetic appeal for polished show engines.
      • Cons: Significantly higher cost. Harder material makes installation more difficult – requires precise tightening to avoid galling (use anti-seize with caution, see installation section). Weight is slightly higher than aluminum.
      • Best Use: Mandatory for high-pressure EFI systems where both pressure and longevity are critical. Strongly recommended for all EFI systems. Excellent choice for high-vibration environments.
  3. Aluminum Fittings:
    • Pros: Very lightweight. Good corrosion resistance (anodized versions offer more). Often used in higher-end AN fittings for racing or performance applications. More affordable than stainless steel for AN fittings.
    • Cons: Lower strength than steel (both tensile and shear strength). Softer than steel, threads can be more easily damaged. Vulnerable to galvanic corrosion if incorrectly mated to stainless steel threads in salt environments (use proper anti-seize). Not typically used for the fitting screwing directly into the pump outlet due to sealing and strength concerns under clamp load – usually found as hose ends or within adapter stacks above the initial pump connection.
    • Best Use: Commonly used for AN-style hose ends and adapters located away from the pump housing itself, especially where weight saving is desired. Less common as the primary fitting screwed directly into the pump port.

Common Sizes: SAE/NPT vs. AN vs. Metric

Fuel system sizing uses different standards, causing confusion.

  1. SAE/NPT (Society of Automotive Engineers / National Pipe Taper):
    • The traditional "pipe thread" standard.
    • Sizes like 1/4", 3/8", 1/2" refer to the nominal inside diameter of the pipe the thread is based on, not the actual thread dimensions.
    • Threads are tapered (get wider as they go deeper) designed to seal by wedging and deforming thread sealant material.
    • Common in stock automotive fuel systems, brass fittings, and lower-pressure applications.
    • Requires thread sealant (Teflon tape or liquid dope) for a leak-proof seal.
    • Fitting sizes relate to hose internal diameter (e.g., 1/4" NPT barb fitting for 1/4" ID hose).
  2. AN (Army-Navy):
    • A standardized sizing system developed for aerospace that has become the performance automotive standard.
    • Sizes like AN-4, AN-6, AN-8, AN-10 correspond to the tube outside diameter (OD) in sixteenths of an inch.
      • AN-4 = 4/16" = 1/4" OD Tube
      • AN-6 = 6/16" = 3/8" OD Tube
      • AN-8 = 8/16" = 1/2" OD Tube
      • AN-10 = 10/16" = 5/8" OD Tube
    • Threads are straight (parallel) and seal using a metal-to-metal flare (37 degrees) or an O-ring (ORB).
    • Offers excellent flow, reliable sealing at high pressures, resistance to vibration, and a professional appearance. Generally more expensive than NPT.
    • Requires specific hose ends compatible with the AN flare or ORB standard.
  3. Metric:
    • Common on modern vehicles and many aftermarket EFI components. Sizes like M12x1.5, M16x1.5 refer to the thread's Major Diameter and Pitch.
      • M12x1.5: Major Diameter = 12mm, Pitch = 1.5mm between threads. Common for various fluid connections.
      • M16x1.5: Major Diameter = 16mm, Pitch = 1.5mm between threads. Extremely common on EFI fuel pump outlets and filter heads.
    • Sealing methods vary – ports can be male or female, and use threads designed for sealing with washers (like banjos), O-rings (like ORB, often labeled M16-ORB), or occasionally even NPT-like sealing (less reliable). Know your port type!
    • Matching metric ports require metric-threaded fittings or adapters (e.g., M16x1.5 to AN-6).

Converting Standards: Matching Pump Port to Hose Line

Very rarely will your pump's outlet thread perfectly match the thread needed for your desired hose end or filter inlet. Adapter fittings are crucial tools.

  1. Identify Port Type: What is on your pump? (e.g., 3/8" NPT Female, M16x1.5 Male with O-Ring Seat)
  2. Identify Desired Connection: What end do you need for the next component? (e.g., AN-6 Male Thread, 3/8" Barb)
  3. Select Adapter: Find the adapter fitting that bridges the gap. It will have two ends:
    • End 1: Must match the pump outlet thread/type (e.g., Male NPT to screw into a female pump port).
    • End 2: Must provide the connection point you need (e.g., Male AN-6).
  4. Common Adapter Examples:
    • Pump has 1/4" NPT Female Port, you need AN-6 Hose. Use: 1/4" NPT Male to AN-6 Male Adapter. Screw the male NPT end into the pump. Connect your AN-6 hose end to the male AN-6 end of the adapter.
    • Pump has M16x1.5 Male Port (with O-Ring Seat), you need AN-6 Hose. Use: M16x1.5 Female O-Ring Boss to AN-6 Male Adapter. ORB fittings seal via an O-ring pressed against a flat boss. Screw the female ORB (has the internal O-ring) onto the pump's male M16 port. Connect your AN-6 hose end to the male AN-6 end.
    • Pump has 3/8" NPT Female Port, you need to connect to a 1/2" ID Rubber Hose with a barb fitting. Use: 3/8" NPT Male to 1/2" Barb Adapter. Screw into pump, clamp hose onto the barb.
    • Pump has AN-6 ORB Female Port, you need AN-6 Hose. Use: AN-6 ORB Male to AN-6 Female Swivel Adapter. Screw the male ORB end into the pump port. The AN-6 female swivel nut allows connection of a standard AN-6 male hose end. The swivel facilitates hose alignment.

Sealing Methods: Getting it Tight Without Leaks

How the fitting seals depends entirely on its type:

  1. NPT (Tapered Pipe Threads):
    • Requires Sealant: Seals by thread deformation and sealant filling imperfections. Never install NPT threads dry.
    • Thread Sealant Options:
      • PTFE Thread Seal Tape ("Teflon Tape"): Wrap tape clockwise (following the threads) 2-3 times over the male threads, starting at the first thread. Do not cover the first thread. Tension the tape slightly while wrapping. Avoid using too much.
      • Liquid Thread Sealant ("Pipe Dope"): Apply a thin, even layer to the male threads. Avoid getting sealant on the first thread to prevent contamination inside the fuel passage. Use sealants rated for gasoline.
    • Tightening: Use correct wrenches. Hand-tighten firmly until resistance is felt. Then, use wrenches to turn the fitting 1.5 to 3 full turns further for sizes common in fuel fittings (1/4", 3/8", 1/2" NPT). Proper tightening wedges the threads. Overtightening distorts threads and causes leaks or damage. Under-tightening inevitably leaks.
    • Flaws: Tapered threads sealed this way are inherently less resistant to high pressure and vibration cycles than flare or O-ring seals. This is why using NPT fittings at EFI pressures is discouraged unless absolutely necessary.
  2. AN / Flared Fittings (37-Degree Flare):
    • Metal-to-Metal Sealing: Relies on precision machining. The conical (37-degree) seat on the male end compresses perfectly against a matching concave seat on the female end. Requires clean, undamaged surfaces.
    • Sealant: NO SEALANT IS USED. Sealant would interfere with the metal-to-metal contact and contaminate the fuel system.
    • Tightening: Requires AN wrenches (thin, hardened, open-end wrenches) to prevent rounding hex corners.
      • Hand-tighten the fitting completely ("finger tight").
      • Place wrenches on both the nut and the fitting body (or pump port).
      • Hold the fitting body still and tighten the nut an additional amount specified for the size. As a general rule (but ALWAYS confirm with manufacturer specs): Small fittings (AN-4, AN-6): Tighten an additional 1/2 to 3/4 turn past hand tight. Larger fittings (AN-8, AN-10): Tighten an additional 3/4 to 1 turn.
    • Inspection: Visually inspect the flare surfaces afterward. They should form a continuous ring of clean contact.
  3. ORB (O-Ring Boss):
    • O-Ring Sealing: Relies on a soft, compressible rubber (usually Viton® for fuel) O-ring trapped between two flat or slightly angled sealing surfaces.
    • Sealant: NO THREAD SEALANT IS USED. The threads only provide clamping force; they do not seal the fluid passage. Sealant is only applied to the O-ring surface if provided (most are pre-lubed).
    • Procedure:
      • O-Ring: Ensure a new, fuel-compatible O-ring (usually Nitrile or Viton) of the correct size is properly seated in the fitting's O-ring groove. Inspect for nicks or flat spots. Never reuse a crushed O-ring.
      • Assembly: Screw the ORB fitting (which contains the O-ring) into the boss port (which has the flat or angled sealing surface).
      • Tightening: Hand-tighten, then tighten with a wrench the specific amount specified (torque value in ft-lbs is ideal). Over-tightening crushes the O-ring excessively, potentially damaging it and leaking or making future removal difficult. Under-tightening fails to compress the O-ring enough.
    • Advantages: Excellent vibration resistance, reliable sealing even after disassembly/reassembly (if the O-ring is replaced), forgiving of minor surface imperfections. Ideal for high-pressure applications.
  4. Banjo Bolts:
    • Sealing: Uses soft copper crush washers (one on each side of the banjo fitting ring).
    • Procedure: Place one washer onto the bolt shank. Slide the bolt through the hole in the banjo connector. Place the assembly against the flat sealing surface of the component (e.g., pump port). Place the second washer over the bolt. Hand-thread the bolt into the receiving port. Tighten the bolt to the specified torque. Compression of the copper washers creates the seal. Always use new crush washers. Never reuse.

Essential Tools for Successful Installation

The right tools prevent frustration and damage:

  1. Wrenches:
    • Correct Size Box-End or Open-End: For standard hex nuts on NPT and metric fittings.
    • Flare Nut/Line Wrenches: Essential for AN fittings (flared). They wrap around more of the nut, preventing rounding. Using a standard wrench on an AN nut will almost certainly round the corners.
    • Crows Foot Wrenches (Optional): Useful in tight spaces, especially with a torque wrench for AN fittings. Match the angle (e.g., 90°) to your access needs.
  2. Torque Wrench: Highly recommended for AN fittings, ORB fittings, banjo bolts, and EFI pump outlet fittings. Achieving the correct clamping force is critical for a leak-proof seal without damaging threads or crushing O-rings. Use an inch-pound torque wrench for smaller fittings (common on pumps).
  3. Thread Sealant (NPT Only): PTFE tape rated for fuel or liquid pipe sealant rated for gasoline/petroleum.
  4. Brake Cleaner / Parts Cleaner & Lint-Free Rags: To clean threads and sealing surfaces before assembly. Oil, grease, or debris compromises seals.
  5. Screwdriver/Pick (Optional): For carefully seating O-rings in ORB grooves without pinching them.
  6. AN Assembly Lubes (Optional): Helps install hose ends onto braided stainless line. Use very sparingly on male threads of stainless fittings if needed for assembly (applied minimally to male thread roots only).
  7. Never: Use channel locks, vise grips, or pipe wrenches on precision fitting hexes unless you want to destroy them. Avoid adjustable wrenches if possible; they easily slip and round corners.

Installation Steps: Leak-Free Connection Checklist

  1. Clean: Thoroughly clean the pump outlet threads using brake cleaner and a lint-free rag. Wipe out any debris from inside the outlet port. Clean the threads and sealing surfaces (flare face, O-ring seat) of your new fitting. Contamination is the enemy.
  2. Prepare Threads (NPT Only): Apply PTFE tape or liquid sealant to the male NPT threads as described earlier. Avoid covering the first thread and getting sealant inside the port.
  3. Hand Tighten: Start the fitting into the pump port by hand. Ensure it threads in smoothly without cross-threading. Cross-threading destroys threads instantly. If significant resistance is felt immediately, STOP and realign.
  4. Initial Seating: Continue threading by hand until it becomes firmly finger tight. For NPT, this means significant resistance. For ORB/AN, this means the fitting/sealing surfaces contact their mates.
  5. Final Tightening:
    • NPT: Use two wrenches – one on the fitting body and one on the pump housing if possible (to avoid stressing the pump mount) or carefully hold the pump securely. Turn the fitting 1.5 to 3 full turns beyond finger tight, depending on size (see sealing section). Stop tightening immediately if you feel sudden yielding/galling.
    • AN Flare: Use AN wrenches. Hold the body of the fitting stationary (if it has a hex). Tighten the connecting nut the specified additional amount (e.g., 3/4 turn for AN-6) using smooth, controlled force.
    • ORB: Use a torque wrench set to the manufacturer's specification for the fitting and O-ring size. Torque the fitting body into the port.
    • Banjo: Torque the bolt to the specified value (a torque wrench is mandatory).
  6. Post-Installation Check: Before connecting any fuel lines, double-check the fitting alignment to ensure the outlet points correctly for your hose routing.

Avoiding Common Pitches: Preventing Leaks and Failure

  1. Under-Tightening: The most common cause of initial leaks. Ensure fittings are sufficiently tightened using the appropriate method. Leaks often appear immediately after start-up or during pressure testing. Recheck torque on NPT/ORB/Banjo; recheck turn count on AN.
  2. Over-Tightening: Especially damaging on NPT (distorts threads), AN (cracks flare seats), ORB (over-compresses O-ring), Banjo (strips threads). More severe than under-tightening; leaks are persistent, and components are often ruined. Prevention: Use a torque wrench where possible. Develop a feel for resistance. Stop when the recommended turn count or torque is reached, even if it doesn't "feel" tight enough.
  3. Cross-Threading: Forcefully starting a fitting off-angle. Results in instantly damaged threads that will never seal. Prevention: Always start threading by hand only. Go slowly. If it doesn't thread smoothly with minimal resistance initially, back it out and try again. Visualize the threads aligning.
  4. Using Damaged Fittings: Never install a fitting with stripped threads, nicked sealing surfaces, or cracked O-ring grooves. Even minor damage causes leaks. Inspect carefully before installation.
  5. Wrong Sealant (or None on NPT): Using Teflon tape on flare fittings clogs and ruins them. Using dope on ORBs is messy. Using no sealant on NPT guarantees a leak. Prevention: Double-check the thread type and sealing method before assembly.
  6. Reusing O-Rings/Crush Washers: Copper crush washers and O-rings are single-use compression seals. Reusing them guarantees eventual leaks under pressure and vibration cycles. Prevention: Always use new, correct size O-rings for ORB and new copper washers for Banjo fittings.
  7. Wrong Fitting Material for Application: Using brass fittings on a high-pressure EFI pump can lead to catastrophic failure if the pressure rating is exceeded. Prevention: Match the material to the pressure. Steel/Stainless for EFI.
  8. Ignoring Vibration: Fuel pumps (especially mechanical) vibrate. NPT fittings are particularly susceptible to vibrating loose over time. Prevention: Use locking compound (e.g., Loctite 243) on NPT threads (follow instructions). Use serrated flange lock washers behind jam nuts if applicable. Consider O-ring or flare fittings where possible as they resist vibration better.
  9. Kinked or Stressed Fuel Line: An improperly routed or unsupported fuel line exerts leverage and bending force on the pump outlet fitting, stressing it and eventually causing leaks or fracture. Prevention: Use appropriate clamps and routing hardware to support lines before and after the pump. Use elbows at the pump if needed to align with the desired routing path smoothly. Avoid sharp bends immediately off the fitting.
  10. Particle Contamination: Debris caught on sealing surfaces (like a tiny piece of PTFE tape stuck on a flare face) prevents proper metal-to-metal contact, causing leaks. Prevention: Meticulous cleaning before final assembly. Cover open ports when not installing immediately.

Pressure Testing: Confirming the Seal

Don't wait for engine start-up to discover a leak. Perform a fuel system pressure test:

  1. Prerequisites: Make final connections from the pump outlet downstream (to filter/carb/rail/etc.), leave the system open temporarily at the very end (e.g., a loose line at the carb inlet, rail port).
  2. Fill: Fill the system temporarily with a non-flammable liquid to purge air if possible (some use brake fluid, though it must be completely flushed afterwards; air testing can be done on certain systems). For critical EFI checks, use air pressure cautiously (consult pump specs first - some pumps can be damaged by compressed air).
  3. Plug the End: Seal the open end you created in step 1 using a temporary plug/cap fitting designed for the pressure (e.g., AN plug cap).
  4. Apply Pressure: Using a dedicated fuel system pressure test pump, introduce pressure slowly to the system at the pump inlet (if possible) or via a port at the filter. Bring it to slightly above the normal operating pressure of your system (e.g., 10 PSI for carb, 75 PSI for EFI).
  5. Inspect: Vigilantly inspect every single connection point – especially the pump outlet fitting(s), fuel line connections to the pump fitting, and all adapters in the stack. Use a flashlight and mirror if needed. Look for bubbles if using liquid, or listen/feel for air leaks if using air (be cautious, do this in a well-ventilated area away from sparks).
  6. Hold: Leave pressure applied for several minutes. Pressure drop indicates a leak you must find. Fix leaks (often requires disassembly, cleaning, re-sealing/re-torquing, replacing damaged parts), then re-test until completely leak-free.
  7. Engine Start: Only after a successful pressure test should you proceed to connect fuel and attempt starting.

Maintaining Your Fuel Pump Fittings

While fittings are generally reliable when correctly installed, periodic checks are essential:

  1. Regular Visual Inspection: During routine engine bay checks, visually inspect all fuel connections, especially the pump outlet area, for any signs of dampness, stain residue, or fuel smell. Address any wetness immediately – it will not get better on its own.
  2. After First Drives: The first few drives are the most likely time for a minor leak to appear (settling/vibration). Re-inspect carefully after initial warm-up and cool-down cycles.
  3. After Major Work: Always reinspect fittings if you've done any work nearby or disconnected lines.
  4. Listen: Unusual noise from the pump region can indicate cavitation due to a restriction upstream (potentially a clogged filter, but also check fittings didn't come loose) or low pressure downstream (a leak). A failed O-ring or gasket within an adapter can also cause noise.
  5. Don't Overtighten Leaks: If you discover a leak after installation, DO NOT simply crank the fitting tighter. This rarely solves the problem and usually damages things further. Instead, depressurize the system safely, disconnect the fuel line, and remove the fitting for inspection, cleaning, re-sealing/replacing components (especially O-rings/washers), and careful reinstallation with correct torque/turn procedures.

Specific Component Recommendations & Considerations

  • Check Valves: Some electric fuel pumps incorporate an internal check valve to maintain residual pressure in the lines after shutdown (reducing hot-start issues in EFI, preventing vapor lock in carbs). If replacing a pump with one that doesn't have a check valve (or has a weaker one), you may lose this benefit. In such cases, an external inline check valve can be installed between the pump and the engine. Ensure the valve body and its fittings are rated for your system pressure and flow. RobbMC Performance offers popular external check valves specifically for SBC applications.
  • EFI Pump Mounting Brackets: When using external EFI pumps, robust mounting is crucial. Vibration kills poorly secured pumps and fittings. Many universal pump kits include basic brackets. Holley, Aeromotive, and others offer dedicated billet aluminum brackets specifically designed to hold EFI pumps securely and may include integrated AN ports and vibration dampening mounts. Ensure the bracket design positions the pump inlet correctly relative to your tank outlet and includes drain-back protection.
  • Universal Pump Kits: Many aftermarket universal fuel pump kits include basic fittings and mounting hardware. Always verify: 1) That the included fittings match your specific pump outlet thread (often kits assume NPT or M16, but check!), and 2) That the fittings match your planned hose size and type (AN vs Push-Lock vs Barb). Don't rely on kit fittings being perfect for your specific application without double-checking.
  • Return Line Fittings: EFI systems require a fuel pressure regulator and a return line back to the tank. The fitting requirements on the pump side for the return line (if applicable) are typically lower pressure than the feed line, and often the same size or smaller. Brass fittings are frequently acceptable here if properly sealed. Still, verify pressure ratings. The outlet port thread on the regulator needs careful identification and proper fitting selection.
  • Surge Tanks & Swirl Pots: These components (common in EFI track cars to prevent fuel starvation) introduce additional inlet and outlet ports that need the correct fittings installed using the same principles outlined above. Thread identification and sealing integrity are just as critical on tank ports as they are on the pump itself.

Conclusion: Invest Time in Getting the Fittings Right

SBC fuel pump fittings are not mere plumbing connectors. They are precision-engineered components that play a fundamental role in the safety, reliability, and performance of your engine. Taking the time to identify your pump outlet threads accurately, understand the different fitting types and materials, select the appropriate size (SAE/NPT, AN, Metric), use the correct sealing method, and install them meticulously with proper tools and procedures is an investment that pays off in leak-free operation and peace of mind. Avoid shortcuts. Match materials to pressure requirements (steel/stainless for EFI). Use torque wrenches for ORB and AN installations. Test your system for leaks before introducing fuel to the system. Regular inspection and maintenance ensure these critical connections continue performing reliably, feeding your Small Block Chevy the fuel it needs to run strong and long. The success of your fuel pump upgrade or replacement hinges significantly on these small but vital parts.

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