Just to put my 2 cents in, I'm in the process of replacing the front springs on my '46 half ton. I had cracked leaves, so I was lucky to find the issue when doing an inspection rather than on the side of the road.
There are a lot of alternatives out there, and I am sometimes suspicious of the knowledge of the people I've spoken with dealing with some vendors. A lot of people seem to be selling generic springs (and other parts) for timespans of vehicles, like '36 to '46 1/2 ton. The spring rates on those years are not the same - those springs are not interchangeable. I am also concerned with substandard outsourced parts. I have had poor luck with some offshore parts in the past - if I can, I prefer to but American. As I understand it, the problem with many replacement springs is that they are not necessarily the same as the OEM in terms of how they flex under load. After looking at a lot of alternatives for springs, I decided to pay more for American quality from OEM patterns, American labor - I'm good with getting what are essentially OEM 1946 springs, except that the steel is probably better quality. I also feel good about spending my money with a Detroit vendor. Your mileage may vary...
