Being a 3B guy, I don't know off the top of my head what the stock springs were, but I do have some advice for you as you consider spring replacement.
The old CJs were all called a 1/4 ton vehicle all the way back to the Army days.
But
If you read the specs, they have a payload of just under 1,000 lbs. That's 1/2 ton by my math.
So
You may correctly expect the rear springs to be rather stiff. An empty Jeep rides llike an empty dump truck.
The suppliers of aftermarket "OEM replacement" springs are following the original specs for the most part. This means you'll have a pretty stiff (see very rough) ride with no load in the back. To prove this to yourself, drive down your favorite bumpy road empty. Then put 500 lbs of sand bags, or something in the back and drive the same road again. Big difference.
I replaced the rear springs on my 3B and have a very bouncy ride. The front springs are fine. When I go over a big bump, the front springs flex as they should and the front end doesn't bounce very much. The rear on the same bump bounces badly - the springs aren't flexing at all - no weight to make them flex.
So
I plan to take the spring packs apart and swap the leaves in the bottom two pairs. That way I keep my spring height and soften them up a lot. I run empty 99% of the time so it'll work for me.
Probably more than you wanted to know.
