Have a 66 Ford with a 302 and 351 heads...heads are new and engine newly rebuilt. Some background: have a smoking problem on the passenger side, (think a ring is stuck) 2 plugs were fouled...we replaced along with new wires (clearance issue). While running noticied some metal "particles" falling...next thing you know...there is a chip on the head where the valve stud should go...there are two chips...and the studs will no longer screw the valve cover on. I have never seen this before and don't know what the heck to do!!!