Hey Steve;
When you say 5/8" left of the pointer are you meaning 5/8" below the pointer? Or maybe your '55 has the pointer in a different location than my '54 which is just above the starter (?)

I've got mine timed so that the BB is just starting to appear in the "hole", below the timing arrow, so I'd say 5/8" below the mark is just about right. Does that make sense?