Yeah, it doesn't take much to get the 350 to run with a stock 400ex. If the mods you have now aren't enough, although it should be if you're jetted properly, the next step would probably be a high compression piston and a more aggressive cam.
I haven't raced one yet I want to race one but people always talk the 400ex to be animal compared to my bike (stock) so I wanted to know what's my chances and what I got 2 do to go faster
Meh, stock 400's aren't much to brag about. You should be able to at least give him a good run for his money the way your raptor is now. A good cam and piston should really seal the deal for you.
Agreed. The 350 is only a hair behind an EX stock, maybe a few mph up top. You should kill him off the launch because he's going to have to worry about keeping his front wheels on the ground, you won't. Put it in second, give it gobs of gas and let the clutch fly. You'll get him off the start no problem....