I have a 98 YZ400F and I did a search for Hot Cams vs. 450 OE Cam. I found a lot of info for a 426 , but nothing for a 400. I am assuming that the 450 OE cam will give the same broad range as it did for the 426 and the 426 Hot cam would be more benefical when used with the intake cam as a pair. I was just wanting to hear from fellow 400's that have done both swaps. I will probably go with the OE cam due to the money situation. Just looking for some info before I make my final decision. Thanks for your time. If this posted twice for some reason I appoligize. Computer has a mind of it's own.