Hi sYc, I've decided to sell these experimental / prototype / pre-production heads that I found and were discussed in this thread (please see thread for photos)
SOLD plus shipping for this match dated 05-27-68 pair of unusual heads.
BBC square port open - came off a running engine, looks like the ports have been cleaned a bit.
https://www.yenko.net/forum/showthread.php?t=155179
I can meet up / deliver in SoCal and will likely have them at the LA Roadster Show this weekend.
Thanks for the interest everyone,
Anthony