Greetings from Johnson City, TN. I'm glad the Ace company still keeps tabs on this forum. Your posts going through the lifetime of the Continental gt 535 ( and other models ) helped a late arrival like myself picture what I'd do with my 2015 model, bought new in March 2020. "The world's more interesting with you in it". Someday I'm going to make an airbox with a foreward facing air intake, but back to this thread.
For clarity sake I think you're stating that the aluminum billet head you designed ( the original subject of this thread ) is out of production, and that you're not commenting on the Clubman Kits ( reworked stock heads ) numbers 1 and 2 that have been offered more recently. A person dropping in late might be confused, but please correct me if need be.
P.S. an overwrought airbox from the rear right.