Rocker arms

No, The factory adjustables had spacers. The crane had springs

Not what I have seen, I have a couple sets of original Big Block Chrysler and one set of Isky adjustable rockers. They all have springs. I even have a NOS set of Chrysler springs. Chrysler usually used a single spacer instead of stacked spacers. That being said, I don't like springs and will be using spacers on the 383 when I build it this summer.