I am looking to get a big bore kit on my 99 400ex. I am wondering if anyone had a 416 kit. Also what size anyone recommends. I do race and some racers told me a 416 will be closer to the performance of a 450 than a 440. Thoughts?

 

Hey man, i have a 2002 440ex. I run with all the 450r's all day long. And my buddy has a 450er with duncan exhast, port and polish, and stage 2 cam, K&N. And sometimes he can out run me and i can out run him. But to save you time. When you go back in the motor to soup it up. Go to GTthunder.com and get the heavy duty studs. Because if not you met have some problems i did. I blow 3 head gaskets, with in 2 hours on the motor. Nowi rebuilt it again with the heavy duty studs, and now have a 6 hours and Still no problems. And i Ride it hard. My 440ex has the BIG BORE kit. 11:1 wisco piston, Stage 2 hotcam. Rev box, K&N, 16 tooth front sproket, GTthunder heavy duty studs, and Duncan full Exhast. It tops out at 83mph. Hope i could help you out........

 

Thanks yea I live right next to gt thunder so that is where I get all my work done... But thanks for the advice!!