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EC 456INT EC Intake Manifold 1.125 HL to Briggs World Formula
456INT EC Intake Manifold 1.125" HL to Briggs World Formula
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EC 456INT EC Intake Manifold 1.125 HL to Briggs World Formula

Part Number: 456INT
Online Price: $48.99
EC 456INT Intake Manifold – Adapt 1.125” Tillotson HL Carb to Briggs World Formula
Availability: In Stock.

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Description

EC 456INT Billet Intake Manifold – Fits 1.125” Tillotson HL Carburetors to Briggs World Formula


Unlock Full Power from Your OHV Open Class Engine


The EC 456INT Intake Manifold is engineered to mount 1.125” Tillotson HL-series carburetors, such as the HL-380 or our exclusive X380-6 Intimidator, directly to Briggs World Formula cylinder heads. (?? Not compatible with Briggs Animal heads.)

Ideal for Open OHV karting classes, this manifold delivers the perfect blend of airflow optimization and precision fuel delivery to extract maximum power from your engine. It’s the go-to intake for competitive racers running open-class engines with cast or billet heads.


Why Choose the EC 456INT with the Intimidator X380-6?

While the HL-380A/B was designed for flathead applications, the X380-6 Intimidator was purpose-built for OHV engines. It’s the most dominant 380-size carburetor in open-class racing, offering:

  • Better airflow efficiency
  • Easier and more precise tuning
  • Optimized fuel circuit for modern OHV configurations

Pair the X380-6 with the 456INT intake for maximum throttle response, superior tuning flexibility, and race-winning performance.


Key Features:

  • Fits 1.125” HL Tillotson carburetors to Briggs World Formula heads
  • Not compatible with Briggs Animal engines
  • Optimized internal shape for laminar airflow and zero turbulence
  • Integrated pulse port for consistent carburetor operation at high RPM
  • CNC-machined from billet aluminum for strength and precision
  • Installation hardware included


Designed for Maximum Air Velocity & Clean Pulse Signal

Each intake is CNC-machined to perfectly match the intake port geometry of the Briggs World Formula head (head shape may vary slightly by model). The result is:

  • No airflow misalignment
  • Strong, consistent vacuum signal to the carburetor
  • Enhanced throttle response and fueling accuracy at all RPM ranges


Tech Note on Intake Length & Signal Strength:

If you're tuning for runner length, here's what to know:

  • Tillotson HL carbs use internal diaphragm pumps that rely on strong intake pulse signals.
  • Longer intakes weaken the pulse, making tuning harder and potentially reducing performance.
  • Optimal length depends on cam profile, port shape, and engine goals—and it’s rarely a “longer = better” scenario.
  • Unless you have dyno time and testing tools, results from intake length tuning may be minimal or even negative.

The 456INT is designed with ideal geometry for Open OHV engines using a 1.125" carb—no guesswork needed.


What’s Included:

  • EC 456INT Billet Intake Manifold
  • Integrated pulse port
  • All necessary installation hardware

FAQ

1. What carburetors are compatible with the 456INT intake?

The 456INT is built specifically for 1.125" bore HL-series Tillotson carburetors, such as the HL-380 and X380 Intimidator.


2. Will this work with a Briggs Animal engine?

No. This intake is not compatible with Briggs Animal cylinder heads. It is designed exclusively for Briggs World Formula heads.


3. Does it support methanol fuel systems?

Yes, the intake is fully compatible with methanol applications and supports diaphragm-pump carburetors commonly used in methanol setups.


4. Is tuning affected by intake length?

Yes. Diaphragm carbs need a strong vacuum pulse. Making the intake too long can weaken this signal and hurt carb performance. The 456INT is optimized for ideal pulse strength and performance balance.


5. Why choose the X380-6 Intimidator over the HL-380A/B?

The X380-6 was specifically engineered for OHV engines, with a tuned fuel circuit and superior airflow characteristics. In contrast, the HL-380A/B was originally designed for flathead engines and may be harder to tune for OHV use.

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