There are several differences between original and reproduction Cobra closed lettered valve covers. The biggest difference is the squared bolt cutout on the originals versus a rounded type cutout on the reproductions. Also the cutouts on the reproduction cut into the second rib at the bottom bolt mounts and top cutouts reach down into the third rib of the covers. On the inside you will notice that the factory installed covers have a number of casting bosses. The oil baffels on the originals are riveted in place where the reproduction are srewed in.