Difference in 273

The spring specs are in the blueprint section of the racing manual and if anyone has a 65, 66, 67 parts manual. I know they are different. They were close to 360 2 barrel springs. I always used 340 springs. They don't float at 330 pounds/inch. Documentation?? 67 Commando 273's and 383 had factory dress items. I've never seen an original Commando or Charger 273 without them.