i don't know the widths of 2188, but we used a 4row wide head on an 8820 a few years ago, dished the wheels in, ran on top of the row but would work, barely, had to also raise the ladder up out of the way too.
I dont see why it wouldnt be able to haddle a 8row. If you contact your dealer or look at the specs. you will find that Case IH "66" (1666,2166,2366) should and will handle the 8 row heads, even up to a 25ft platform.