My WR400 has developed a rattle in the motor. I suspect it is a rod bearing, or so I've been told by some TT'ers. Anyway, assuming I have to rebuild it, can I put a 426 crank and piston in the 400 motor assuming I rebore the cylinder? A friend has a good 426 crank and rod. Also, can you guys recommend a good engine rebuilder who can do a quick turnaround? Thanks.