True, but when i first got my cossie and rebuilt the engine, and not knowing much about them sent the head off too have new guides fitted etc. Then when i was gonna put it back on the bloke who was helping who hadnt seen it b4 it went to them noticed how much it had been skimmed and basically it was skimmed too much by whoever had it before!! So was pretty useless. At end of day it was my/our fault for not realising but any decent machine shop should/would check things like that spec when doing something like fitting valve guides which cost me about £200