Home > Performance Engine Parts > Camshafts And Lifters > Big Block: GX240, GX390, 420 Predators And Clones 11/13 HP Chinese OHV
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250 "Twister" Nitrited Performance Camshaft, GX270s to 390s & 420 Predators 280 Series Camshaft - (GX240s to GX390s) 306 Series Camshaft, Honda GX240s to GX390s, 420 Predators, 460 OHV

The "Twister" is a High-performance grind providing significant power increase over the stock cam at a great price. Developed on the dyno and the track to maximize power on GX270s, GX390s, 420 Predators and 13/15hp Chinese OHV.
Great All Around Riding Cam

Stock lift with increased duration and optimized valve timing for a wide powerband (2000-5000+ rpm) providing a drastic improvement throughout the entire RPM range. This cam is easy on the valve train and will not "beat up" your valves or lifters.


Recommended for Yard Karts, Mud Motors, Short Track Go-Karts, Marine, Pulling/Towing, Mini-Bikes and anywhere else where a broad powerband is a needed and loss of low end is unacceptable. Also great for racing classes that require stock lift.

Cams is cut on a close base circle to the stock cam so the compression release is still functional.

  • 246 Duration
  • .260" Lift using stock rocker arms
  • (.250 at lobe)
  • 110 LSA (ICL varies depending on engine installed in)

Use HD Single Valve Springs Only (no dual springs)

 		The Torque Cam, massive amounts of low end power for Marine, Mini-Bikes, and Small Tracks.
306 SERIES - Race cam with awesome mid-range power
Serious race cam with awesome mid-range power camshaft for serious motors. Lobe designed esp. for Honda 270 - 390 Motors. Approx .306 lift and 240 duration (at .050). This cams likes big carbs and big ports. Best Cam for 240 to 301cc (esp GX270s) engine.
Best HP Cam for GX270s, Also great for 390s wanting excellent Torque
0410 Torque Grind - 6500 RPM. 9.0 to 1 compression or more. Requires HD or Dual Springs (recommended), Small track cam for serious torque. Works on both 270s and 390s.
0807 RPM Grind - 7500 RPM. 11.0 to 1 compression or more. HD or Dual Springs Required, Recommended for 270s needing high rpm HP. Great all around Cam for 390s.

Note: Honda Blocks or crankshaft may require clearancing to clear camshaft lobes.
Fits Honda GX240 thru GX390, 420 Predators, 460cc OHVs, and most other 9 thru 15 hp Honda Style OHV Motors
Will not fit 414 LCT motors and some 301 Predators with large journals
Camshaft, 307 Series, Honda GX240s to GX390s, 420 Predators, 460 OHV Dyno Cams Mod 1 Camshaft (welded) - World Formula, w/Compression Release Dyno Cams 356 Camshaft, GX390, 420, And 460

ALL OUT RACE CAM FOR BIG BLOCKS (GX390s and 11/15 hp Honda Style OHVs)

307 SERIES camshaft for serious motors and big tracks. Approx .307 lift and 260 duration. This cam was 6 month in development. Special Ramp Designed for running 12 to 1 or higher compressions using Race Gas or Methanol. Use with Dual springs and 1.3 rockers.
This is the cam for 30+ hp motors. RPM Grind - 7,500+ RPM. 12.0 to 1 compression or more. Dual Springs Required, High HP grind for 1/4 mile+ tracks.

Note: Honda Blocks or crankshaft may require clearancing to clear camshaft lobes.

Fits Honda GX240 thru GX390, 420 Predators, 460cc OHVs, and most other 9 thru 15 hp Honda Style OHV Motors

Will not fit 414 LCT motors and some 301 Predators with large journals
This cam makes slightly more top end power than the 308 grind. This cam requires an upgraded spring package, billet rod, and billet flywheel.
Engine: 13HP Honda GX390

INTAKE
  • LIFT: .310
  • Dur @ .050": 247.6 Deg.
  • C/L: 108 ATDC

EXHAUST
  • LIFT: .310
  • Dur @ .050": 247.6 Deg.
  • C/L: 108 BTDC

THE LOBES ON THIS CAM ARE WELDED. Note: Block or crankshaft may require clearancing to clear camshaft lobes

 		Approx .356 lift, . Small Base Circle. Welded and Ground*
Note: Block or crankshaft may require clearancing to clear camshaft lobes. For GX270, GX390 and 13/15hp Chinese OHV
Dyno Cams P-Open Camshaft GX390 and 13/15hp Chinese OHV
The P-Open is intended for a full tilt modified or open class. This cam offers larger duration with a lower lift. Upgraded valve springs, billet rod, and billet flywheel are mandatory. A 33mm or larger carb is recommended. The lobes are welded to increase durability, extending the life of this cam.
Dual springs required.
The lobes are welded to increase durability, extending the life of this cam.
Specs
  • Engine: 390cc Honda GX390, 420cc Predators, & 13/15 hp Chinese OHV
  • Recommended Class: Modified / Open
  • Target (MAX) RPM: 8000+
  • Spring Pressure (In / Ex): 65 lbs Dual Spring
  • Valve Lash (In/Ex):.003"
  • Ignition Timing:110 Octane 34 Deg BTDC, Methanol 38 Deg BTDC
  • Compression Ratio:12.5 to 1 or Higher
INTAKE EXHAUST
OPEN: 71 BTDC 89 BBDC

CLOSE: 88 ABDC 50ATDC

LIFT: .363" .367"

C/L: 106.0 ATDC 110 BTDC

DUR@50 263 DEG 269 DEG