Actually Joe, I just stuck the Torroidal head you made on a stock 66.5mm cylinder, set the squish to 0.030, and it out performs the stock 72mm Vitos Big Bore Kit cylinder I have, especially in low end grunt and mid-range. (3mm stroker, airbox is opened up, FMF pipe and carb is jetted through plug reading) The BBK might have a bit more guts just before it peaks, but barely.
I'd like to try the hemi head on this cylinder but Neil won't dream of letting it go.
Re-chambered heads are the first mod you should make to these machines folks.
Don't go too crazy on compression or it will get hot and wear out early.