Yenko ZL-1 ?

[GMH454]

I know I have read that Pickett used a " Yenko " in his Trans BBC Vette when he won the 78 Trans Am. Now if it was a 52 block cast by Yenko I'm guessing it would have been called a ZL-1. Think I have been told by Vintage racers that it was one of the larger castings, similar to a Can Am in size. It's not proof of a late 70's casting date, but the article was dated 1978.
I have seen three different "Yenko" blocks.
1. With crest
2. The one here with Yenko script small and neat,
3. one with Yenko script, larger than above and on an angle(its under my work bench ..with liners bored 90th over)

We use more about this stuff all the time, but this makes me realise how far we have to go.
Don left way too soon.