I'm getting ready to buy an '04 450 EXC. And I've been told that putting a 525 cam in a 450 will change the top end. Now, I work at a Shop and have a Mirca Fiche(spl?) and found out that the cam is the same in the 400/450/525 in 04. BUT, the '03 cams are diff, altho still using the same cam in all three modles. At least they appere to be. Has anybody had any experience in what I'm talking about...any help is much appreciated.