1988-91 Cr 250 big bore 300 Excellent condition for its age built by klem research in 1990 no power valve sealed off custom wisco piston probably still available not sure I left the head on as it requires a custom bored out gasket that would have to be modified it’s ported out extensively the piston has some wear but was running fine before tear down this thing is fast you have to run richer jetting and ritch mix for best results Shipping lower 48 only