Maybe bad news. I think you will need to remove the so called partition or cover over the terminals as it may interfere w/the headers, pending which ones you have. Common problem but minor. Maybe if you remove it, you won't need a larger terminal.
So, I checked the clearance between the starter and the headers, and I have about 2.5 fingers of room between the header and the closest stud. When the shop installed my engine, they installed it quite a bit forward, plus I have TTi shorty headers. Also, one of the holes is larger than the 7/16" bolt (9/16" hole to be exact) so I took some measurements and found a $1.14 bushing from McMaster to fit in the starter and prevent slop (McMaster P/N 9368T143 9/16" OD, 7/16" ID, 0.5" Long - McMaster-Carr). I also got some terminals from work, so that should work out well.