According to this search result using GM parts wiki, that "w" spring was used for all 1947 truck models. Looks to be a one year only use according to the screenshot I have attached below. No idea on how it found it's way onto your '48? The GM#s for L-hand and R-hand springs are shown in the pic. A quick web search found no results to show any NOS parts or reproductions available currently.
Your call on trying to make some replacements, but I think the standard springs would do the job with a bunch less fuss than trying to recreate those springs. Let us know what you decide to do and how it works out.
~ Dan 1951 Chevy 3 window 3100 Follow this story in the DITY Gallery "My Grandpa Carl's Truck and How it Became Mine" 1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver) US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)
