I haven't run the engine with the valley breather yet. I'm in the middle of complete engine re-shuffle with my 470 engine turning into two different 470 engines.

I do have batwings on hand in both the std port as well as the MW port size. I haven't tried the MW port size on an engine yet myself but I've sold some to folks who gave me a thumbs up on the fitment. There are a lot of different MW port sizes floating around as well as different gasket sizes so it wasn't a perfect one-size-fits all solution.