Interesting question, so I did some research.
Noland's Vol 2 shows a factory picture of the '66 L79 with 7-fin aluminum valve covers and a decal on the air cleaner cover (page 359).
But, the decal section of his book (page 57) states that no decals were used on any '66 327ci air cleaner, and that the '66 L79 had only a single "350 Horsepower" decal on each valve cover.
Interestingly, the air cleaner decal in the page 359 picture (not easily readable) shows a dark top ("327") & bottom ("350 Horsepower") with a light center ("turbo-fire"), which is the opposite of all the air cleaner decals shown in the decals section, which have a darker background reading "Turbo-Fire" in the center section and lighter upper & lower sections. Vendors sell this latter version
Page 288 shows an illustration and several pictures of the '65 L79, which show the positioning of the decals on the aluminum valve cover (and no air cleaner decal).
I'm inclined to believe Noland's verbiage that only the valve cover decals were used in '66, also.
Someone possessing a '66 NCRS Judging Manual may have more definitive information.
