Sure nailed it down for me. You are splitting it hairs. He gave a generalization. Over 550 up to 600. Work with it. If you could, put together a combo that exceeds 550hp but not 600.
The one thing missing is the camshaft specs of what is being used, unless I missed it. Rich Holdner explained everything really well IMO. While the 210cc’s of the Indy head are greater by 20cc, more than just a fair amount larger, the stroker should still do well with it. I’m not to sure about a single plane use w/3.55 gears and a smallish cam would be a great idea but a TF head and a moderate cam would really be good on the street.