I think you would probably be able to get a filter with a 3.25” (82.55mm) ID flange to work? It’s only about a millimetre difference. Probably zero difference with the O-rings installed on the inlet.
I had a quick look online and here are a few AEM ones.
AIR FILTER; 3-1/4"FLG, 6"B, 5-1/8"T, 9-1/8"H
www.aemintakes.com
AIR FILTER; 3-1/4"FLG, 6"B, 5-1/8"T, 5-1/4"H
www.aemintakes.com
AIR FILTER; 3-1/4"FLG, 6"B, 5-1/8"T, 7"H
www.aemintakes.com
I couldn’t seem to find the ability to search AFE on their own website like you could before, but I’ve found this one, I’m sure there are others.
With three layers of progressively finer mesh synthetic "oil-free" media between 100% polyurethane frame top and base, this high flow, "oil-free" conical performance filter provides maximum convenience and easy maintenance with excellent airflow. Washable and reusable for multiple cleanings, the...
afepower.com
You might need to get some pipe or a silicone elbow or something to tilt the inlet entry away from the block and provide space for the filter. Or cut off the bracket and rotate the inlet and figure out a way to hold it to the block?
I intend to design something 3D-printable with a standard MAF profile and PCV heater port, but I’ve already got so much to do!