Mind you, some roads were still dirt back then too. Being 'paved' was well..... rare. Going 35mph on a pot hole filled country road with a 3/4 ton and higher truck would just about send the driver through the roof I'd say.
My 50 GMC 1.5ton in high can prob. go 50 mph, unloaded. Might make 50 loaded if the road is flat or slightly sloped down. And I used it to haul full bins of apples up until 9 years ago. Use your ears... if it sounds too loud, prob. means you're going to fast.
My 52 GMC 3/4 can barely make it to 45 with its ratios....
