Upgrading from kelsey hayes to???

IMO,that article is flawed. As area lot of HR articles
The discs in the back did not decrease the stopping distance, the drums were simply not tuned to potential; and we both know why.
Sorta like ET and trapspeed.
For street;
I find no fault in rear drum brakes, having driven most of my life with them; some tuned, most not. I PREFER them on the back over discs, as they are, in my experience, trouble free. Just about every all-disc vehicle I have ever had (including my wife's and my three kids) have had, at one time or another, rear brake troubles. And some of them were a total PITA to service, especially with the parking brake system fubared into them.
But hey, it'd good that you shared.