This is stuff that you can only know by dyno pulls and time slips. Dodge did not leave much on the table in terms of HP when it comes to the cam, years ago the stock cams were terrible and one of the first thing that was done was to throw out the stock cam. I have a .455 lift purple cam in my 340, right out of the Direct Connection catalog, they had pages of purple shaft camshafts and listed exactly what cam was needed for a 14 second through a 9.5 second small block (same as for a big block).
Now, that stock roller cam is just killer, the only improvement, IMO is on the high end. There is a charger hellcat (Omega) going 9.03 on stock motor, stock IRS, just a pulley and some spray, that is how good the stock cam is.