Trivia: After Sylvester has swallowed the bowling ball, he goes back down the drainpipe and out into the street. When this happens, look behind him and you can see a sign saying "Drink Friz! Six Delicious Flavors" - a reference to the director Friz Freleng. There is also a building with "Champin's 5 and 10" on it - a reference to the animator Ken Champin.
Continuity mistake: When we see Tweety singing, you can see that the bottom of his cage has nothing on it, but when we see Sylvester next to the cage, a door has appeared.