There were a bunch of different Yenko alu blocks. Some had "YENKO" in block letters cast in, some had a Yenko crest cast in, some had no Yenko ID, some had water jacket, some were solid blocks, and other different designs. They were used in boats, drag, sprint, road racing etc. They were also working on an alu V6 but don't know if that project was completed.
I believe there were at least two different companys used for casting and two different companys used for machining as Yenko changed the vendors over the years.
Warren D., the Yenko employee who as original paperwork from Yenko Chev, has a bunch of stuff on the alu blocks. Mark G. is working on putting this into together for a new book. They have receipts showing some big names in all forms of racing.
He has receipts for A J Foyt, Pat Musi and others
I have some pictures, Yenko ads, and old magazine articles on engine builds using Yenko blocks.