Used KX420 stroker kit, comes with crank assembly, used original piston, new set of standard rings and spacer plate. Kit originally came with exhaust chamber(missing) with above parts. Crank will need new lower bearing and need to be trued. Piston is already modified for kit installation. I also have copy of original instructions. You will also need two cylinder gaskets that are easily obtainable. Turn that vintage kx420 into a 450 beast. Kit is very rare and impossible to find as well as piston and new rings.