I was being sarcastic about the hoses and bolts. The listing is pretty ridiculous with "custom" preceding every feature, but not even the valve sizes or flow numbers are mentioned.
If you OND or if you 65SC or anybody get time tell
us why it's worth that and what will it do that a $300 head
can't do? Is it mainly for alcohol go-kart racing-motor compression ratios ?
Value is entirely subjective; I can't speak to that. I can postulate as to why somebody would use one.
Billet heads, assuming they are well-designed, have thicker decks for better head gasket retention and more potential to be milled. They typically can accommodate larger valves, ports, and flow than a cast head. The chamber can be whatever size and shape is desired. It's a practically a clean where all the shortcomings of a stock design can be addressed, which is why I'm always disappointed to see a billet head with a bathtub chamber and inline valves. At least it looks like they had the sense to use a 10mm spark plug.