From my experience, best place(s) to buy Winfield stuff is at swap meets. Ebay prices are outrageous and you can't really tell what you're getting.
Saw two Winfield heads at Chickasha pre-war meet last year and the year before...$550 for a yellow head and $700 for a red head. Both probably needed a light surfacing for cleanup.
I bought my yellow head (early production - 18mm plugs) a couple years ago for $500; it ended up having a small crack between the water passages that I had repaired and needed .025" removed from the surface to clean/true it up. Got my Winfield SR-B carb and matching intake at a swap meet around the same time - $600 (I've seen incomplete carbs on Ebay go for similar prices).
