I also love these old cartoons, but if they're for your 3 year old granddaughter, then soz no way.
I have a 3 year old daughter, and I grabbed some old school Tom and Jerry for her to watch. she started acting out the behaviour from these cartoons. Hitting people with various things, pinching, claiming 'it doesn't hurt them', running around smashing things etc.
Banned tom and jerry, and her behaviour improved.
Now, many months later, she still remembers them and begs me to bring them back.
For 3 year olds, I suggest Pingu, Pocoyo, anything from Pixar or Dreamworks.
For yourself, if you really wanna see old cartoons, I suggest *cough* Bittorrent *cough* Piratebay *cough*.
The 1920/1930s B+W cartoons have the best drawing styles I ever saw - Popeye, Felix the Cat etc. In a sensible world, they'd be out of copyright now and free to all.
I'm not suggesting censoring cartoons for adults, but I do suggest that it is unwise to consider ultra-violent cartoons as suitable for infants.
It's the same as some japanese Manga/ Anime, even if it has high quality storylines, lovely art, and you yourself love it, it's still maybe not appropriate for infants.