Bilge Port Supply Ventilator

I just purchased an older (1985) 36' convertible. The port side clam shell ventilator hood is cracked on the mounting flange, and I would like to replace it. This is the raised blower intake ventilator located on the walkway. The original part number is 043089X. I have contacted Sam's, but they do not have this part, and it has been replaced, on newer boats, with a clam shell located on the hull, with a part number of 043091X. If anyone can help me find the part, I need, I will be greatly appreciative. Thank you.