I can’t drive – SEVENTY FIVE! Or can I?

I've got a question that probably shows my lack of mechanical know-how, but I don't mind looking dumb so I'm going to ask:

Are these big, old Chryslers ok to drive interstate speeds of 75 or higher for long distances? This is of course only in situations where the car is mechanically sound. I ask because they were made when highway speeds were 55 mph. I want to make trips to Denver (or further) which is 90 miles one way but it sounds like I need my rear end rebuilt in my '73 Fury and I want...

I can't drive - SEVENTY FIVE! Or can I?