hey my buddy gots a z with the 450 yosh stroker kit. the timing chain busted on him and trashed his head and piston. he's lookin at a big bore kit from rockymountainatv that takes it to 94.5 mm bore, hes at 92mm from the strocker kit. is that a good idea to go with? since it got his cylinder wall as well? also his head is trashed! does yosh do anything to it when they put there kit in? i couldnt find any sign on there sight but we need ta know how much we need to do to a new head to match it back up? or mod it further? and does anyone know the compression ratio on that kit?? thanks guys