The original Heinrichs Curly Block was a very fine Va/Per. Then manufacture was turned over to STG around 2016 or 17 and they changed the composition of the blend, adding a dark Cavendish (IIRC) core to it. Still a good blend, but not like the original, which reminded jiminks of the Murray's Dunhill Navy Rolls.
BTW, Dunhill never made Navy Rolls. That was a Murray's addition.
I still have some of the original. You need a diamond tipped cutter to slice it, because it's so damned dense.