Which one's are You referring to, the Tahuil Co., or the 24v DOHC Cecares Formula SP one? The date of the Tahuil Co. one is a mystery, I'm really just trying to fill a little historical void in, a company involved in a complete redesign & casting of a Slanty head had to have more irons in the fire..
The link that takes you back to .org says circa 1969 for the magazine picture it was in, so who knows how much older the heads actually were prior to that, but over 50 years old at this time.
