Hi all I think my post about valve cover bolt holes may have caused further confusion and I apologize if that was what happened. I should have said what was possible due to cylinder head interchangeability regarding this, so that it did not imply that the factory did anything like that. My 62 , both my 63's had 4 bolt covers, and had never been disassembled before. A 64 we dismantled last year had 6 bolt, but I have seen both on 64 and 65 Chryslers not just Imperials. I cant say that all of these cars were in fact original engines and that the cylinder heads had not been swapped for later ones. Sorry to cause any unneeded confusion Mikey 62 Crown Coupe