420cc Engine Kit for GX390 The ultimate kit for high-revving GX390s!
Billet steel crank, producing 440cc
ARC billet rod
Forged Diamond 90mm flat-top piston
Piston rings
Tool steel wrist pin & clips
Puts piston at TDC. *Note: This is not a bolt-in kit, but for experienced engine builders. Available unbalanced or fully balance (not needed for most applications).
