Re using cast iron rings?

I wouldn’t just run new rings, but I’d go as far as to splurge on a set of phosphate coated (proffered) or hard chromed rings. But the last time I checked, the 3.91 inch bore narrows that selection down to a hard chrome top and phosphate coated second ring. And a torque plate home back to round with the proper finish, since it’s all apart anyway.