440 big bore kit?

[440 00]

i bought a used 400 ex with 440 kit well i took the top half off to look it over and i replaced the piston from 11:1 to 12:5:1 do i need to change the valves becuse it has a raised dome now or can i run it the way it is

[sixer3]

you should be able to run it that way somone please say something if you think otherwise, be sure to use race gas, and get some heavy duty head studs, and i would recomend buying a heavy duty rod and crank if you dont want problems down the road, 12.5:1 is a lot of pressure my friend, good luck with it