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EC Dual Valve Spring Set for GX390/420 & V-Twin Engines
270 EC Dual Valve Spring Set
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EC Dual Valve Spring Set for GX390/420 & V-Twin Engines

Part Number: 270
Online Price: $21.95
Availability: In Stock.

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Description

EC 270 Dual Valve Springs – GX390, GX420, Briggs, & Predator V-Twins


The EC 270 Dual Valve Springs are built for high-lift camshafts, extended RPM ranges, and racing durability in big block engines. Engineered specifically for performance applications, these dual springs are compatible with Honda GX390, GX420, Briggs & Stratton V-Twins, and Predator 670 platforms.


These are the same valve springs used in our championship-winning race engines—delivering increased valve control, RPM stability, and reliability under extreme conditions. Ideal for high-lift cams and aggressive cam profiles, these springs are a proven solution for race builds needing maximum performance without valve float.


Note: Call us for the correct retainers for your specific application. No warranty due to the nature of racing use.


Spring Installation Heights & Theoretical Max Net Lift:

Your install height must be measured per cylinder head for accurate fitment and performance.

Install Height

Seat Pressure

Theoretical Max Net Lift

1.400"

27 lbs

.675"

1.300"

43.5 lbs

.575"

1.200"

60 lbs

.475"

  • Uninstalled Height: 1.600"
  • Open Pressure @ .725" lift: 148 lbs
  • Coil Bind Height: 0.680"

Net Lift = (Cam Lift × Rocker Ratio) – Valve Lash

Depending on your valve train weight, rocker geometry, and cam acceleration rate, spring pressure alone may not ensure full control. Choose install height based on your actual build specs.


Spring Dimensions:

Outer Spring:

  • Outside Diameter (OD): 0.987"
  • Inside Diameter (ID): 0.743"
  • Relaxed Length: 1.608"
  • Wire Diameter: 0.115"

Inner Spring:

  • Outside Diameter (OD): 0.725"
  • Inside Diameter (ID): 0.570"
  • Relaxed Length: 1.470"
  • Wire Diameter: 0.076"


Compatibility:

  • Honda GX390 & GX420
  • Briggs & Stratton V-Twin
  • Predator 670
  • Clone/Performance Big Block Cylinder Heads

FAQ

Q1: What engines are the EC 270 valve springs compatible with?
A: These dual springs are designed for high-performance builds using Honda GX390, GX420, Briggs & Stratton V-Twin, and Predator 670 engines. They also work with modified big block heads and aftermarket setups.


Q2: What camshafts or lift ranges are these valve springs designed for?
A: They support high-lift cams in the .475"–.675" net lift range, depending on install height. Seat pressures range from 27 lbs to 60 lbs for reliable valve control at high RPM.


Q3: What is the recommended install height?
A: Install height depends on your specific cylinder head and build. Here are typical ranges:

  • 1.400" = 27 lbs @ .675" lift
  • 1.300" = 43.5 lbs @ .575" lift
  • 1.200" = 60 lbs @ .475" lift
    You must measure your actual install height for best results.


Q4: What retainers do I need with these valve springs?
A: Retainer selection depends on your valve stem size and keeper type. Call us for guidance on choosing the correct retainers for your application.


Q5: Are these springs covered under warranty?
A: No. Due to the extreme stress of racing environments, these valve springs are sold as-is with no warranty. We recommend inspecting spring condition regularly in competitive builds.

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