Try this website. Very close to me and had a chat with Martin there a while ago. He was saying that he had achieved comparable/greater flow rates as with Guy's heads a couple of years ago..
https://deltaparts1.wordpress.com/Hi Mick,
Many thanks for your kind reply.
As a matter of fact, I have recently met Martin over the e-mails as I was working on Tipo 16v engine for a customer friend of mine. He has been very helpful and supplied the parts that I needed. Great communication we had.
But I didn’t know he was also involved with the TC engines.
As I am in need of a stage1/2 spec properly prepped cylinder head for a road going 131, I will talk to Martin then.
Regards
Kerem