I'm sure this has been discussed before so pardon my ignorance and I apologize if I am bringing it up again...but here's my question: Will the exhaust cam from a 450 work on my 02 YZ426 without making any modifications? Other than having the auto decomp is it the same, i.e., same lift and duration as the 426 cam? Does it matter which model year 450? Also, what do you do with the existing release valve? Does it help with low RPM stalling?