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356 Camshaft - Honda GX390/Big Block Clone
.356 Lift Camshaft - Honda GX390/Big Block Clones
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356 Camshaft - Honda GX390/Big Block Clone

Part Number: 356-GX390
Online Price: $149.99
DynoCams 356 Camshaft for Honda GX390 & Big Block Clone Engines
Availability: In Stock.

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Description

DynoCams 356 Camshaft – Honda GX390 & Big Block Clone Engines


The DynoCams 356 Camshaft is an all-out, high-lift racing camshaft engineered for Honda GX390 and big block clone engines built to operate at extreme RPM. This camshaft is designed for high-flow cylinder heads that continue to gain airflow above .400” valve lift and for engines running large carburetors to maximize top-end horsepower.


This is a competition-only camshaft and is not recommended for mild builds or engines operating below 5,000 RPM.


Designed for High-Lift Ratio Rocker Systems

The DynoCams 356 features a .356” lift profile, which exceeds .400” total valve lift when used with ratio rocker arms. Due to the high lift and aggressive nature of this camshaft, significant cylinder head and valvetrain preparation is required, including:

  • Thick-wall chromoly pushrods
  • High-pressure dual valve springs
  • Billet roller rocker arms
  • Lightweight valves and retainers
  • Increased installed spring height and adequate coil bind clearance

This camshaft is best paired with billet cylinder heads or heavily modified cast heads that maintain strong airflow at high valve lifts.


Performance Characteristics

The DynoCams 356 Camshaft is a popular choice for maximum-effort, high-flow engine combinations. It performs exceptionally well with billet cylinder heads featuring large valves and big ports, which are capable of taking full advantage of the cam’s increased lift and duration.

This camshaft is designed to maximize peak torque and horsepower at high RPM, making it ideal for engines built with:

  • Lightweight forged pistons
  • Billet connecting rods
  • Lightweight billet flywheels
  • Balanced rotating assemblies
  • High-flow billet cylinder heads
  • 36mm or larger carburetors, ideally on methanol
  • Lightweight yet robust valvetrain components

When properly matched, the DynoCams 356 delivers hard acceleration, rapid RPM climb, and high top-end speed in competitive racing environments.

Idle quality will be very rough in most combinations, particularly when using ratio rockers and billet heads. Higher clutch stall speeds may be required to prevent off-idle hesitation. This camshaft is not intended for recreational use.


Built for Extreme Durability

The DynoCams 356 Camshaft features a hard-welded lobe design, providing excellent wear resistance in high-RPM, high-spring-pressure racing environments. Due to its aggressive profile, upgraded dual valve springs are mandatory for proper valvetrain control and long-term reliability.


Recommended Supporting Components

To fully unlock the performance potential of the DynoCams 356 Camshaft, the following components are strongly recommended:

  • 36mm or Larger Carburetor
  • Billet Connecting Rod
  • Billet Flywheel
  • Billet Roller Rocker Arms
  • Thick-Wall Chromoly Pushrods
  • Big Valves & Porting (Billet Heads Strongly Recommended)
    Larger valves and professional port work significantly increase high-lift airflow and allow the engine to fully capitalize on the cam’s aggressive profile.


Fitment

  • Honda GX390
  • Predator 420 Wedge (Non-Hemi)
  • Wildcat 460
  • Cam Boss Diameter: 16mm (.628")

Important: Camshaft-to-block and camshaft-to-rod clearance must be inspected during installation.


Technical Specifications

Engine Platform: Honda GX390 / Big Block Clone
Recommended Class: Modified / Open
Target Maximum RPM: 7,600–7,800 RPM
Valve Spring Pressure (Intake / Exhaust): 65 lbs Dual Springs
Valve Lash (Intake / Exhaust): .003"


Ignition Timing Recommendations

  • Pump Gas: Not Recommended
  • 110 Octane Race Gas: 34° BTDC
  • Methanol: 38° BTDC

Recommended Compression Ratio: 12.5:1 or Higher


Camshaft Timing & Lift Specifications

Specification

Intake

Exhaust

Open

51.6° BTDC

94.0° BBDC

Close

93.5° ABDC

54.8° ATDC

Lift

.3555"

.3555"

Centerline

108.0° ATDC

108.0° BTDC

Duration @ .050"

254.3°

254.5°


Why Choose the DynoCams 356?

  • High-lift racing cam for extreme GX390 builds
  • Optimized for billet and high-flow cylinder heads
  • Designed for large carburetors and methanol setups
  • Excellent high-RPM horsepower and acceleration
  • Hard-welded for durability in open-class racing

FAQ

What engines is the DynoCams 356 camshaft designed for?

The DynoCams 356 camshaft is designed for Honda GX390 and big block clone engines, including Predator 420 Wedge (Non-Hemi) and Wildcat 460 platforms. It is intended for modified and open-class racing engines only.


Is the DynoCams 356 camshaft suitable for stock or mild builds?

No. The DynoCams 356 is a competition-only, high-lift camshaft and is not recommended for stock, mild, or recreational builds. It performs best above 5,000 RPM and requires extensive supporting modifications.


Do I need a billet cylinder head to run the 356 camshaft?

A billet cylinder head is strongly recommended. While heavily modified cast heads can be used, billet heads provide significantly better airflow above .400” valve lift, which is where the DynoCams 356 excels.


What valve train upgrades are required for the DynoCams 356?

Due to its aggressive lift and duration, the DynoCams 356 requires:

  • Dual valve springs (65 lbs or higher)
  • Thick-wall chromoly pushrods
  • Billet roller rocker arms
  • Lightweight valves and retainers
  • Proper spring installed height and coil bind clearance

Failure to upgrade the valvetrain can result in component failure.


What carburetor size works best with this camshaft?

A 36mm or larger carburetor is recommended. This camshaft is commonly paired with methanol fuel systems to support high RPM airflow and peak horsepower.


How does the DynoCams 356 compare to lower-lift GX390 cams?

Compared to lower-lift cams, the DynoCams 356:

  • Produces significantly more top-end power
  • Shifts the power band higher in the RPM range
  • Sacrifices low-speed torque for peak horsepower
  • Requires substantially more supporting modifications

It is designed for maximum-effort racing, not versatility.


What idle quality should I expect?

Idle quality will be very rough, especially when used with ratio rockers and billet heads. Many combinations require higher clutch stall speeds to prevent off-idle hesitation.


What compression ratio is recommended?

A minimum compression ratio of 12.5:1 or higher is recommended. Higher compression improves throttle response and maximizes the camshaft’s high-RPM efficiency.


What ignition timing works best with the DynoCams 356?

  • Pump gas: Not recommended
  • 110 octane race gas: 34° BTDC
  • Methanol: 38° BTDC

Proper timing is critical for durability and performance.


Is this camshaft suitable for karting, drag racing, or oval racing?

Yes—when used in open or modified racing classes, including:

  • High-RPM kart racing
  • Drag-style acceleration builds
  • Lightweight oval or dirt track applications

Chassis weight and traction should be considered due to the aggressive power delivery.


Does installation require clearance checks?

Yes. Camshaft-to-block and camshaft-to-rod clearance must be checked during installation. This is mandatory for all high-lift racing camshafts.

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