Winter, we also experimented with moving to cylinder head around on the deck surface. We did see some negligable gains, but found that just unshrouding the chamber was the best and most effective way to get bigger gains. I know of several top Comp Eliminator racers that today currently have even moved the intake valve centerlines away from the bore toward the exhaust valve, and have gotten the same results as if they unshrouded the chamber with the valve in the stock location. They are currently using a 21 cc chamber that was been completely redesigned and reshaped. Also long gone are the familiar lump style intake ports, this has been abandoned almost 10 years ago by most all of the top frontrunners still using the siamese heads in professional racing, in favor of more modern technologies, and are experiencing intake ports with flow #'s over 400 CFM. Thats pretty amazing, since the Ford guys are allowed to use the AJ Billet head for their engines, and thats about the same flow #'s they are getting from them, so its pretty cool, that a 30+ year old head casting can perform closely to a state of the art billet head. I think you can see that even the chamber itself still needs to be unshrouded when using big valves, and that just moving the head around by itself doesn't eliminate or correct that, it only corrects the cylinder shrouding which is a different issue. When using a 2.150" intake valve as we did, you have to notch the top of the cylinder to unshroud it. It also is helpful to do this on smaller valves also, especially if you don't have a big cylinder overbore.
