My friend has a 04 honda 450r and he bought a stage 1 hot cam we started to put the cam in and found out about the shims in the cam and we wanted to know if u have to have them i figured yes becaeus it has a higher lift and it would make clerancees tighter but in it never hurts to be shure and some one told me the that stage one need valve and head work is this true. we are used to the old school type stuff on the 400 ex where stage 2 needs extras