50 amp, 240 volt hookup without equipment ground

Although I have seen it done on many post-WWII houses, my current house built in the '70's has the sub-panel setup I described. The main panel on the side of the house has the 240v services - A/C, Range, HW - while there is a separate sub-panel inside the house with all the 120v services on it. There is no ground extended from the Main to the Sub. It's just the way it was done until a couple of decades after WWII. Not correct these days and not as safe as a fully grounded system.