xl 350 question

[reconmaster]

so my cousin is rebuilding his old xl350 street/trail bike. he cant get a honda piston and has problems gettin a wiseco. is it possible for a xr/400ex cylinder to fit? how much machine work and parts would be required to work

[SRH]

i dont beleive there even close to the same size bore, what yr is his 350? i may have a cylinder and piston