Does anyone know the true significance of the "O" stamping on 60's SBC valve covers. I have always thought/been told that the "O" stamp was only used on factory chrome valve covers. The theory seemed to hold until I was cleaning up a set of 65-66 painted covers today. These covers look be be in their original paint with the embossed 327 decals/foils. While cleaning the covers, I noticed they both have the factory "O" stamping on the inside rail. Was this stamping for covers that came out stamped with no flaws an therefore were chromeable? Or maybe these painted one were a factory mistake? I thought it was interesting enough to share.
Jason