I wanted to put a 426 motor in my 99 WR400. The rod end bearing at the crank pin failed and I hear the 426 is the most reliable of the WR's. My 400 is California plated so I really want to keep it but I don't want to rebuild it only to have it fail again... Do you know if I can bolt the 426 motor into my 400 frame? I don't know if the outside dimensions of the motors are the same or not, I heard that the 450 motor requires a few adaptations to make it work and maybe the electric start would make that worth my time and effort. I would like to hear from those who know what will interchange with the 400 and what won't.