I'm always amused when someone thinks they have to change the driveline in an old vehicle to make it "safe", or so they can drive it "anywhere they want". Most of them never go any distance in the cars after they have made the modifications. Even most devoted street rodders never range very far from home.
Old cars are fun BECAUSE they go slower and take more time to get where you are going. More time to enjoy the ride, smell, sound, and approving waves of the folks along the way.
I like driving my 1926 Model T Ford. But the improvement in just 9 and 10 years to my '35 Chevy Coupe and '36 Chevy truck, is astounding. The Model T, of course, was already out of date when it was built.

Mike