Patricks, in Arizona, carries them - $390 for the pair. I put them on my '48, and I've very happy with them. However, you need to realize that you'll also have to lower the rear unless you want the truck to "lean" forward. Patrick's sells a lowering kit that includes the front springs plus lowering blocks, shackles and shocks for the rear for $500.
They're not much for
web presence , but they know AD trucks inside and out, and they're good people who can be trusted. (Not saying that Brothers can't be.)