Back in December (2008) we had a long thread (#530608) when I replaced my sagging 100-6 springs. I had only 3" of ground clearance.
5-10 years ago, I bought a set of springs and had never installed them.
The bad news is that these springs were designed and built for a BJx and I have a 100-6. The BJx has a 1" drop in the frame at the rear axle that the 100-6 does not have, so these new springs would NOT be a plug & play.
The good news is that these springs were built by Martin Jansen at Jule. My 100-6 springs where 6 leaves of 3/16 thick spring stock and these Jule springs were 5 leaves of 1/4" spring stock.
When I talked to Martin, he told me that for a BJx, the height of the middle of the spring stack over the end eyes (standing eyes down on a table) was 3 5/8".
These new springs were a little too stiff for my "Cruisin'" taste so I ended up using the top two 1/4" leaves from Martin's springs and the bottom 3 leaves from the original 100-6 springs.
When I installed the new spring, I had to add a 1" spacer block between the axle perch and the spring stack to compensate for the frame drop.
My car is apart for the installation of a R&P steering unit, a 24" radiator, and air conditioning. I haven't had a chance to put any miles on it, but the ride height looks good (I picked up 1" of ground clearance) and in only a ride around the block, the ride felt good.
The ride may require a little "tweaking" when I get back on the road in a couple of weeks.
From my experience and in from hearing from others, I would NOT recommend re-arching. It won't last.
I WOULD recommend calling Martin at Jule and hearing what he as to say. He may still have some springs to sell. Knowing Martin, I think that his products will be better then the others.
Tim