Earlies date for 3964291 L78/L72 heads?

[Mr70]

Have him do a pencil tracing.

[Rixls6]

I saw the ad for these on Ebay. This is the 3rd set of this style '291' head I've seen. I think these must be '78 or maybe even (though doubtful) `88 castings.
I saw a set like these that had a casting date something like 'E080' which would not be 1970, as those 70 dated heads had 70 as their casting date, not just an 0 for the year.
Hope I haven't confused the situation.
Notice the 'CFD" that is not on the original style 69 thru 75 castings. Also the casting number '3964291' looks completely different than the early design.

[John Brown]

Maybe they aren't K 28 8, but really K 2 88 instead.

[bigchevydaddy]

Are they big or small sparkplug? Wouldn't the small 'peanut' plugs mean a later manufacture date?

[Jeff H]

Yeah, that "CFD" looked odd to me. Thanks for all the suggestions. I really think they are later dated 291 heads and not late 68/early 69 heads.