Re: bellhousing for my 351w is for a chevy!!!
Your second picture showing the original IH contains the clue. The 'plate' in the background performs one of the same functions that the 'spacer' plate does in mine. They would not have both.
Additionally, it appears that your bell is deeper than mine. That would account for the lack of need for the 'spacer'. Examining the holes, looking at them side by side, they look very similar with a few differing in size. I can't tell which ones might be threaded and which ones are not.
Seems like you are good to go with a few modifications of holes. I guess that OMC finally made a universal V8 bell housing.
Sorry for the false alarm. Don't forget to lube that TruCourse steering cable while you have it out.