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

Part Number: 315-GX390
Online Price: $149.99
DynoCams 315 Camshaft for Honda GX390 & Big Block Clone Engines
Availability: In Stock.

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Description

DynoCams 315 Camshaft – Honda GX390 & Big Block Clone Engines


The DynoCams 315 Camshaft is the natural step up from the popular .308 camshaft, designed for builders who want additional top-end horsepower without giving up the strong low-RPM torque big block engines are known for. Positioned above the Mod1, the 315 delivers increased airflow demand and higher RPM power while maintaining a balanced and usable power curve.


Most GX390-based big block engines produce ample torque by design. The .315 profile takes advantage of this by shifting more power to the upper RPM range with minimal torque sacrifice, making it ideal for modified and high-flow racing builds.


The DynoCams 315 excels as a “low-lift” cam option for extremely high-flow cylinder heads, particularly billet heads with larger cross-sectional area, larger valves, and 34mm or larger carburetors. This combination provides an excellent balance of low-speed torque and high-RPM horsepower.


Designed for Ratio Rockers

The 315 features a .315” lift profile engineered specifically for use with 1.2 or 1.3 ratio rocker arms. This allows most modified cylinder heads to achieve just over .400” total valve lift while maintaining proper valvetrain stability and reliability at elevated RPM.


Performance Characteristics

The DynoCams 315 Camshaft is closely related to the .308 grind, sharing a similar lobe separation angle while incorporating increased lift, duration, and overlap. These changes extend the power band and improve top-end performance, particularly in engines with sufficient airflow to support the added duration.

Gains are most noticeable when paired with ported cylinder heads, larger valves, and high-flow induction systems, where airflow improvements allow the cam’s timing to fully translate into usable horsepower.


While the 315 retains much of the predictable behavior of the 308-style profile, idle quality may become rougher when combined with higher ratio rockers, larger ports, and big carburetors, which is expected in high-output racing applications.


Built for Durability

The DynoCams 315 Camshaft features a hard-welded lobe design, significantly improving wear resistance in high-RPM, high-spring-pressure environments. Due to its aggressive performance profile, upgraded dual valve springs are mandatory to maintain valvetrain control and long-term durability.


Recommended Supporting Components

To fully unlock the performance potential of the DynoCams 315 Camshaft, the following components are strongly recommended:

  • 34mm or Larger Carburetor
  • Billet Connecting Rod
  • Billet Flywheel
  • Billet Rocker Arms
  • Chromoly Pushrods
  • Big Valves & Porting
    Larger valves and professional port work raise the effective power band and significantly extend top-end horsepower. Big block engines naturally produce strong low-RPM torque, so increased airflow does not negatively affect bottom-end performance.


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
Target Maximum RPM: 7,500 RPM
Valve Spring Pressure (Intake / Exhaust): 50–55 lbs Dual Springs
Valve Lash (Intake / Exhaust): .003"

Ignition Timing Recommendations

  • Pump Gas: Not Recommended
  • Race Gas (110 Octane): 32° BTDC
  • Methanol: 36° BTDC

Recommended Compression Ratio: 12.25:1


Camshaft Timing & Lift Specifications

Specification

Intake

Exhaust

Open

49.80° BTDC

99.65° BBDC

Close

98.80° ABDC

63.05° ATDC

Lift

.3135"

.3135"

Centerline

108.0° ATDC

108.0° BTDC

Duration @ .050"

249.65°

253.40°

Duration @ .200"

154.90°

156.95°

Why Choose the DynoCams 315?

  • Ideal step above the 308 and Mod1 camshafts
  • Excellent low-lift option for high-flow billet cylinder heads
  • Strong top-end horsepower with minimal torque loss
  • Optimized for ratio rocker configurations
  • Hard-welded for durability in competitive racing environments

FAQ

What is the DynoCams 315 camshaft best used for?

The DynoCams 315 camshaft is best suited for modified and high-flow racing builds using Honda GX390 and big block clone engines. It is designed to increase top-end horsepower while maintaining strong low-RPM torque.


How does the 315 cam compare to the 308 and Mod1 camshafts?

The 315 cam builds on the 308 and Mod1 profiles by adding slightly more lift, duration, and overlap. This allows the engine to make more power at higher RPMs, especially when paired with high-flow cylinder heads and larger carburetors.


Is the DynoCams 315 considered a low-lift cam?

Yes. Despite its increased performance, the 315 is still considered a low-lift cam, making it ideal for engines with very high-flow billet or ported cylinder heads where airflow efficiency is prioritized over excessive lift.


Can the DynoCams 315 camshaft be used with ratio rocker arms?

Yes. The .315 lift profile is designed for 1.2 or 1.3 ratio rocker arms, allowing most modified cylinder heads to achieve just over .400” total valve lift while maintaining valvetrain stability.


What supporting components are required with the 315 cam?

Upgraded dual valve springs are mandatory. A billet connecting rod, billet flywheel, billet rocker arms, chromoly pushrods, and a 34mm or larger carburetor are strongly recommended for reliability and performance.


Does the DynoCams 315 camshaft have a rough idle?

Idle quality may be rougher than a 308 or Mod1 cam, especially when combined with high ratio rockers, large ports, and big carburetors. This camshaft is intended for competition use.


What engines does the DynoCams 315 camshaft fit?

The DynoCams 315 camshaft fits Honda GX390, Predator 420 Wedge (Non-Hemi), and Wildcat 460 big block clone engines with a 16mm (.628”) cam boss.


Does installation require clearance checking?

Yes. As with all high-performance camshafts, cam-to-block and cam-to-rod clearance must be inspected during installation.

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