Will it work?
i could swear i'd seen threads about it, but can't find them now.
i know there isn't much metal on the head for port matching. But will it basically seal?
Pretty sure some have done it with no issue the opposite of what you a re doing, D port with an oval manifold. So I see no reason it wouldn't "work". It will not be optimal for a max HP engine, but I bet you don't notice a thing.