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Engine, Racing, Open Modified, Honda GX390
Engine, Racing, Open Modified, Honda GX390

Our Price: $1,870.00

Stock Status:(Out of Stock)
Part #: ENG-RAC-GX390-LM

Head Casting (Application)

GX390 Small Port (High Torque, Wide Power)
Large Port (Max HP, High RPM) [+$11.2]
Select Piston/Rings

Aftermarket Cast Flat-Top
OEM Dished Piston
Forged Flat-Top, Std Bore [+$169]
Forged Flat-Top, 90mm Bore [+$235]
Select Carburator

Carburetor, 24mm Bored 3-Circuit Carb - Gas
Crankshaft Type/Options

OEM Honda Crankshaft
.160" Stroker Crank, Cast, Balanced [+$239]
.200" Billet Stroker Crank [+$411] Adds Labor for Clearacing
Select Rocker Arm Type

1.2 Billet Roller Tip Rockers
1.2 Roller Rockers (includes Spacer) [+$144]
Select Camshaft

306 HP (Med to large tracks)
306 TQ (Small Tracks)
307 RPM (33mm Carbs or Bigger Carbs)
Select Flywheel

Billet Aluminum
Small Diameter Aluminum (NA with Electric Start) [+$49]
Billet Aluminum with Digital (PVL) Ignition [+$150]
Add Fuel Tank & Pump Options

Additional Options

Balance Assembly (included on strokers) [+$142]

Add Billet Side Cover [+$208] Adds Billet Side Cover to GX390s

Add 40mm Intake [+$64]

Extended Starter Nut for Handheld Starter (No Recoil) [+$23.1]

Description -

Honda GX390 Race Engine. Highest quality Big Block available.

Engine includes:

  • Open Element Air Filter Assembly,
  • Removal of governor,
  • Advanced Timing,
  • Billet Steel Rocker Arms
  • Billet Rod
  • Billet Flywheel
  • UT1 Coil (w/o Rev Limiter)
  • Full Ported & milled Head,
  • SS Valves (OS on intake)
  • Aluminum Retainers & keepers
  • Dual Springs (Single with TQ cams)
  • Choice of cams
  • Chrome Moly Pushrods
  • ARP Bolt Kit
  • Choice of Carbs
  • Dyno Tested


  • Roller Rockers
  • Mikuni Carbs
  • 90mm Bore
  • Small Diameter Flywheel
  • PVL Ignition
  • Stroker Crankshafts

Engine Size Options:

88mm (Std) Bore, Stock Stroke : 390cc

88mm (Std) Bore, +.160” Stroke : 414cc

88mm (Std) Bore, +.200” Stroke : 420 cc

90mm Bore, Stock Stroke : 407cc

90mm Bore, , +.160” Stroke : 433cc

90mm Bore, +.200” Stroke : 440cc

Filter should be sprayed with K&N type oil, especially in dirt applications. Oil not included click here.

Billet Stokers cranks come with balance shaft

Engines are built to order and take approx 4 to 6 weeks

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