MJV: You might search around for a GMC Master Parts Book, Models 100-450, Published 1958 or 1959 and covers Y, X, T, and, S series trucks. I am not aware of reprints of this book, but they might be out there.
I see them on eBay from time to time but it will take a fair amount of diligence to find one. It will be invaluable to you.
