Choke well insert?enclosure?

My Slant 6 exhaust manifold has an open choke well leading directly into the exhaust port. This type/year factory manifold utilizes a stamped steel insert under the actual choke assembly to seal the exhaust port against leaks. I need this insert. Didn't know what to call it so forgive the word choice. Prefer using Paypal to pay but can get/send USPS money order also.