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EC 447INT 1-Inch HL Spigot Intake Manifold
447INT 1.00" HL Spigot Intake Manifold
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EC 447INT 1-Inch HL Spigot Intake Manifold

Part Number: 447INT
Online Price: $31.99
EC 447INT Billet Spigot Intake – Fits 1.00" Tillotson HL Carburetors
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Description

EC 447INT Billet Spigot Intake Manifold – 1.00" HL Tillotson to Spigot Port


Adapt 1.00" Tillotson HL Carburetors to Spigot-Style Manifolds


The EC 447INT Spigot Intake Manifold is a precision CNC-machined billet adapter originally designed to fit a 1.00" throttle bore Tillotson HL carburetor to a Briggs World Formula spigot-style intake manifold. It also serves as a versatile solution for adapting HL-series carbs to custom engines using spigot ports and hose-type insulators.


Built for performance and flexibility, the 447INT provides a clean and reliable connection, allowing diaphragm-style carburetors to operate efficiently in custom or racing engine configurations.


Key Features:

  • Fits 1.00" bore Tillotson HL carburetors only
  • 1.300" OD spigot for hose-style mounting to compatible manifolds
  • Integrated pulse port in flange for diaphragm carburetor function
  • Ideal for custom small engine builds, World Formula engines, and kart racing applications
  • CNC-machined from high-quality billet aluminum for strength and precision


Fitment Notes:

  • Does not fit 1.125" HL carburetors – pulse hole will not align properly
  • Requires a hose or boot that matches both the 1.300" spigot OD and your intake manifold port


Why Choose the 447INT?

Many stock cylinder heads limit intake airflow due to restrictive bolt spacing. The 447INT enables higher-flow performance by allowing your HL diaphragm carb to be mounted via a spigot-style intake, removing the limitations of traditional flanged bolt-on setups. Perfect for custom builds, welded manifolds, and high-RPM methanol race engines.


Technical Specifications:

Specification

Details

Throttle Bore

1.00"

Spigot Outer Diameter

1.300"

Pulse Port

Yes (for diaphragm carb use)

Material

CNC-machined billet aluminum

Carb Compatibility

Tillotson HL-series (1.00" bore)

Manifold Compatibility

Spigot-style (via hose/boot)


Use Case Examples:

  • Briggs & Stratton World Formula engines
  • Custom kart builds with spigot intake ports
  • Methanol racing engines using diaphragm-style HL carburetors
  • Builders welding their own intake manifolds for better airflow and tuning

EC 446INT vs. EC 447INT Spigot Intake Manifolds

Feature

EC 446INT

EC 447INT

Carburetor Compatibility

Tillotson HL (1.125" throttle bore only)

Tillotson HL (1.00" throttle bore only)

Incompatible With

HL carbs with 1.00" or 1.060" bore (pulse port misalignment)

HL carbs with 1.125" or 1.060" bore (pulse port misalignment)

Throttle Bore Diameter

1.125"

1.00"

Spigot Outer Diameter

1.300"

1.300"

Mount Style

Spigot (hose or rubber boot mount)

Spigot (hose or rubber boot mount)

Pulse Port

Yes – pre-machined in flange

Yes – pre-machined in flange

Installation Type

Hose/boot connection to spigot-style intake manifold

Hose/boot connection to spigot-style intake manifold

Use Case

High-performance methanol engines with welded intakes or spigot ports

Methanol racing engines using 1.00" HL carbs, World Formula setups

Original Application

Adapt 1.125" HL to spigot-style manifolds (e.g., custom heads)

Adapt 1.00" HL to Briggs World Formula spigot intakes

Material

CNC-machined billet aluminum

CNC-machined billet aluminum

FAQ

1. What carburetors are compatible with the EC 447INT?

The EC 447INT is specifically designed for Tillotson HL-series carburetors with a 1.00" throttle bore. It is not compatible with 1.125" or 1.060" HL carbs, as the pulse hole will not align properly.


2. What size is the spigot connection?

The intake features a 1.300" outer diameter spigot, which is designed to fit most rubber hose or boot-style insulators commonly used with spigot manifolds.


3. Does it include a pulse hole for diaphragm carburetors?

Yes, the EC 447INT includes a pulse port in the flange, ensuring proper fuel pump operation for diaphragm-style HL carburetors.


4. What types of engines or setups is this intake designed for?

It was originally built for the Briggs & Stratton World Formula engine, but it also works with custom race engines, welded spigot intakes, and any application using a spigot-style manifold with a 1.00" HL carb.


5. Can I use this on a 1.125" HL carburetor?

No. While the mounting may look similar, the pulse port will not align on 1.125" carbs. For those, use the EC 446INT instead.


6. What else do I need for installation?

You’ll need a hose or boot that fits both the 1.300" OD spigot and your engine’s intake port. This part does not use a flange/gasket system—it relies on a secure hose connection.


7. Why choose a spigot intake over a traditional flange?

Spigot-style intakes offer better airflow, simplified mounting, and more porting flexibility—especially useful for custom-built engines and methanol-fueled applications where traditional flanged intakes may restrict performance.

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