I wouldn't use it, unless you think your engine has 70 years of gunk solidified in your engines nooks and crannies that might be dislodged if modern detergent oil is used.
The only person I personally know who uses non detergent, straight weight oil in certain of his classic cars does so in a couple J model Duesnbergs and Packards of the 1930s that have their original engines that have never been rebuilt and have had non detergent oil since day one.
The rest of the vehicles in the collection, where worries about dissolving impurities in the crankcase aren't a concern, use modern detegernt , multi-viscosity oils.
I wouldn't use zinc additives, either. You can't control how the additive is blended with the oil or in what ratio.
If you really want a high zinc oil for your engine, The Classic Car Club of America has contracted to have oil produced to its own specifications for use in antique car engines. It has 1600 ppm ZDDP, which is about the highest zinc content of any oil you'll find, including the VR-1 racing oils.
www.inrccca.org
