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EC GX390/420/440/460 Carburetor Velocity Stack
328VS EC Infinite Radius Velocity Stack
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EC GX390/420/440/460 Carburetor Velocity Stack

Part Number: 328VS
Online Price: $24.99
EC 328VS Velocity Stack for GX390, Clone 420, Predator 420 Carburetors
Availability: In Stock.

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Description

EC 328VS Billet Velocity Stack for GX390-GX420 Big Block Engines


Unlock peak airflow and increased engine performance with the EC 328VS Billet Velocity Stack—precision-engineered with a radiused design that accelerates and smooths incoming air, boosting both velocity and vacuum signal at the carburetor.


This velocity stack is designed specifically for big block stock carburetors, and it’s an essential upgrade for racers looking to optimize intake performance in classes where velocity stacks are permitted. Whether you're building a high-performance kart, mini bike, or other small-engine application, this stack provides a measurable advantage in throttle response and fuel delivery.


Key Features:

  • Radiused entry improves airflow and enhances intake signal strength
  • Precision CNC-machined from durable 6061-T6 billet aluminum
  • Optimized for stock carburetors in big block applications
  • Designed to fit 2.625” ID air filters (check fitment before ordering)
  • Includes mounting hardware for quick, easy installation


Engine Compatibility:

This velocity stack is made to fit stock carburetors on the following big block engines:

  • Honda GX390
  • Clone 390 / 420
  • Predator 420
  • Wildcat 460
  • Most GX390-style big block clones

Also fits small block engines when using a GX390-style carburetor adaptation.


Racing Tip:

Velocity stacks outperform plain filter adapters by reducing airflow turbulence and improving fuel atomization. We highly recommend using them in every racing class where they are legal. Always check your sanctioning body's rulebook before competition use.

FAQ

Q1: What does the EC 328VS velocity stack do?

A: It improves airflow into the carburetor by using a smooth, radiused entry, which increases air velocity and enhances the vacuum signal. This leads to better throttle response and more efficient fuel atomization.


Q2: What engines is this compatible with?

A: It fits stock carburetors on the following engines:

  • Honda GX390
  • Clone 390 / 420
  • Predator 420
  • Wildcat 460
  • Most GX390-style big block clones
    It also fits small block engines when using a GX390-style carburetor conversion.


Q3: What size air filter does this stack fit?

A: It’s designed to fit 2.625” ID air filters. Be sure to check your air filter’s dimensions before purchasing.


Q4: Is this legal for racing?

A: In many open or modified classes, yes—but always check your rulebook or racing organization guidelines before use.


Q5: How does this differ from a plain filter adapter?

A: Unlike a basic adapter, the EC 328VS uses a radiused design that improves airflow efficiency. This can result in better throttle response and a stronger fuel signal—especially important at higher RPMs.


Q6: What’s included with the EC 328VS?

A: The velocity stack includes:

  • 328VS Billet Velocity Stack
  • Mounting hardware

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