Well to stroke the motor you have to pull the crank out and have it turned which is expensive to have done. The 426 piston will give you the power you need. Thatis what I have and it rips. Beating some 440's. If I were you just stick with the 426
2000 Honda 400ex, 426 JE piston, Hotcams Stage 2 cam, Ported head, Uni Air filter,WB Rev box White Brothers Pro-Meg exhaust, TCS ZPS fronts, TCS rebuilt ZPS rear, IMS desert tank. IMS Bumper, Tinner airscoops, AC Propegs, Edelbrock Carb, PEP stabilizer, Durablue X-33 axle, Houser +2 a-arms. Maxxis razer rears. 15/36 gearing
AIM naterbwillard