My '37 doors were hard to close once I installed all the weather stripping, over time it got easier. Clean and grease the latches, and make sure the catches on the door frame are free of burrs and not worn out and adjusted right. Even when working good, my inside pull knob is pretty hard to pull, but that's better then the door coming open on its own. The door handle has a square rod that engages the square door latch, if either one is worn, the handle droops, same with the internal latch wear, it all adds up and the handles droop. I gave up trying to fix mine, now every so often I change the rubber grommet in the outer chrome trim piece which will holds the lever up while at a show or cruise night, but they still droop while driving.
I though about figuring out just how much they droop, then twisting the square rod enough to take out all the slop so the handle would set level, but I only had one pair and was afraid of what might happen if it went south.