Timken tapered roller bearings are design to be ran with preload on them, how much depends on the application. those on the 3rd member carriers in rear ends get a lot more preload than the front wheel bearings should have
That being said there is no way I would drive any of my early model Mopars with any front wheel bearing hubs having any up or down free play after adjusting the bearing preload, SOMETHING is WRONG with yours, I think
When i was a lot younger, back in the early 1960s, I worked in several different service stations, now know as gas stations, and did a lot of lube jobs which would include removing the front brake drums and hubs to remove and inspect and then clean and repack the good wheel bearings, replace any than had any obvious visual issues on the bearings or races
GM cars back then, especially Chevy, had ball bearing in the front hubs, they were way more sensitive to the proper front wheel bearing preload adjustments