I have no experience with any large bore SB stuff…….so I can’t comment on that.
IMO, a good place to get higher flowing factory SB heads ported to “high” flow is KG engines in Ohio.
Edit-actually I do have a small block large bore SB story……
I use a 4.00” bore for testing most SB stuff.
I had a few heads come thru here that had been ported elsewhere, where my flow numbers were noticeably less than the ones supplied by the porting service.
I wondered if perhaps they had been tested using a larger bore……..so I tried it.
Basically zero difference.
