Has anyone tried to stagger the valves?
That is move the exhaust closer to the spark plugs and move the intakes closer to the manifold. The closer that you could get a line between the valves to be on the center of the bore the larger the valves could be. The hybrid heads move the pushrods away from the block by some angle. What is maximum angle from vertical you can angle a pushrod and still have it stay in the lifter at rpm. I'm sure there are limits with a stock head, but a custom head. Even if it required a wider valve cover that might not be a bad price to pay depending on how close to the center of the bore you could get.
Larry
