Bill - According to the 1955.2 Chevrolet Truck Engineering Features booklet, that same power steering system is listed as "Optional Extra Cost Equipment" for all Chevy trucks except forward control models. I'd have to confirm through other Chevy Master Parts Books, but I think it's applicable from 1955.2 - 59. Same diagram in my referenced resource as what you posted.
~ 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)
