+1 are u sure the fork and frame front tube is not milled ISO?, are u sure the tange falcon is jis?? I believe that thing is iso after looking at velobase, either way a jis crownrace should fit just fine, more than fine it is too big.

Another thing, why not use the old crownrace?? probably it will work just fine with the new headset, did you try???? If it works and is not pitted u can save 20 bucks re using it.