I have big block with Brodix heads which use the same "porcupine" compund valve angles as the head above.
It works but watching the rockers etc as you turn it over I am never sure why.
The pushrods have to be restrained by the slotted guides which whilst they don't always touch the pushrod certainly leave a slight rubbing mark on the pushrod.
As the pushrod comes up it causes the rocker arm to "wipe" across the valve stem head to reconcile all the conflicting arcs. My rockers have roller tips and I wonder if the rollers are slight slightly curved to help the wiping motion.
The things can run at 6,500 rpm as they did in CanAm days.
The latest GM BBC engines are 632 cubic inches , yes nearly 80 CI per cylinder, but have new symmetrical heads so the famous staggered intake ram stacks of CamAm fame are no longer needed.
They give 1,000 bhp out od the crate!