Dear David,
I'm sorry that I am unable to supply you a twincam cylinder head to fit your engine (240/300cu/in) but I can give you an option .
I have a demo motor for sale which I can ship to you .It is a complete engine .250 cu/in Falcon/Mustang Twincam engine.It has done aprox 15000 miles .This is a fully operational engine with the following features;
Twin CDI ignition systems complete ,3 x side draft 45 mm Webber carbys with manifold and all linkages,10:1 comp ratio -super or unleaded compatable, set up for air-con and power steering.This is a complete Mustang engine,250cu/in instead of 200cu/in,ready to slot straight in.Auto or manual. No fuss! No hassles! No worries! Press button start-instant go.This engine will deliver aprox 400 HP @ 6000RPM. Your cost would be $4750 usd including freight to USA .
If you are interested ,I can send you some email photos.Kind regards , Bob Krogdahl