I do think you’ll have to port match. I had a Indy rectangular intake years ago. These are the as cast port sizes for a W5.
Take note these as cast ports are not well cast and are wider in the middle, pictures below. I used the Dig/Caliper as a pointer.
The port width and height are 1.13/1.14 - 2.29-2.31.
The widest point is 1.19, that’s a .060 difference.