It took me one time 35 years ago to make sure any old car I might buy would have disc's or do a swap. We had the local hangout behind a field and I had driven slowly through a very very deep puddle with my 66GS. The drums got soaked. I pulled out to the road and then decided to test my brakes. Absolutely nothing, I was STANDING on the pedal and surprised I didn't pop a seal on one of the wheel cylinders. The stars lined up that day because the road was usually busy but not that time. I'm guessing I traveled 1/8 of a mile before it started to brake. Maby some higher friction shoes would of helped but I was young and on a tight budget. On a normal or heavy rain day it was minimal but I don't want to go through that again.
That is exactly what I was referring to... I had a 71 Nova and 65 Chevelle that were like that and after updating the Nova to disc front brakes, I swore I would always do that to any future car I had with front drums.
It was petrifying wasn't it?? Maby if hit the brakes off and on it would of helped but at that point I was looking ahead to were I maby could drive off the road safely.