I have a set of very nice "186" heads that look to be completely original and correct except the combustion chambers have the valve un-shrouding machine work on the intake AND exhaust valve walls of the chambers. Not a deep cut by the exhaust valves but looks to be factory. No port work mods at all. The valves are the special GM swirl polished type so I think they are original to the heads. Have any of you seen this exhaust valve wall cuts before?