I think the bottom line is that we're at a severe disadvantage simply because of the small bore spacing. None of the current head offerings even come remotely close to what the competition has available off the shelf.
Without a 5" bore space block and heads to match we're just going through the motions. you can only get just so much valve in a 4.8" bore space chamber and at a max 4.560 bore in most cases, we aren't even close to having a head with a better runner design and valvetrain to match.
Without power adders there's just so much you can do. I hate to put it that way but that's the way it is.