Distributor advance springs

Yeah. I got my new bearings. But I’m gonna try and accumulate the other parts I want over the winter and tear it down next spring. On the bearings tho, I’ve noticed the main bearings I bought say they’re for a 76-83 slant or whatever but they’re the same width as the bearings for my earlier slant. I was under the impression that all the bearings were narrower on the cast cranks. Is that true or are just the rod bearings narrower? Did I buy the wrong mains?
The mains & rods are both different, correct. No way those are correct unless they are boxed wrong, or Your old engine is also a cast crank, one or Dee udder.