**OUT OF STOCK**These engines are custom made to our specifications and are the only 458cc Honda GX390 "big bore clones" available for purchase in the United States.
This kit doesn't include Piston, rings, rod, cam, valvetrain, pull starter or balance shaft. If you need those pieces, we do sell them individually.
The builder kits are designed for those who are experienced builders/racers and/or building an open motor in which many of the stock components will not be used.
Why throw away the stock parts when you dont have to buy them in the first place??? Our builder kit includes the following:
*4.51" Rods are ONLY compatible with the Flat-Top Cast Piston
*4.45" Rods are ONLY compatible with the Forged Pistons