So can u take the top end off the 500 and put it on the 400
Well,it's not exactly that easy...ATV Racing does a conversion to allow a 500 cylinder to be used on a pilot lower end...It requires re-locating the cylinder studs,lots of case welding,and port matching....It is somewhat expensive,but does make better torque,and 500 cylinders are easily available....Their conversion price includes the case mods,a cylinder,piston,and a pipe to work on the cylinder...Last time I checked it was somewhere around $3000....
Hoodlum