1. Henry Winkler, who was playing Fonzie on "Happy Days" (1974), was originally supposed to play Danny but didn't for fear of being typecast.
2. Susan Dey and Deborah Raffin were the first choices for the role of Sandy (Dey declined after her manager advised against it). Marie Osmond later claimed on the Larry King Show that she had been also been offered the role but declined "on moral grounds." She later admitted this to be untrue.
3. Due to a zipper breaking, Olivia Newton-John had to be sewn into the trousers she wears in the last sequence (the carnival at Rydell).
4. Jeff Conaway had to walk slightly stooped so that John Travolta would appear taller.
5. Set in high school, most of the principal cast were way past their teenage years at the time of filming. John Travolta was 24; Jeff Conaway, Michael Tucci, Barry Pearl, and Didi Conn were all 28; Olivia Newton-John was 29; Jamie Donnelly was 30 and Stockard Channing was the eldest at 34. Dinah Manoff and Lorenzo Lamas were still teenagers - both were 19.
6. Carrie Fisher was considered for the role of Rizzo.
7. For a time, it was the third highest grossing movie of all time behind only Jaws and Star Wars .
8. The film was released in Spain as Brilliantina (Brilliantine) - because its English title translated as "fat" in Spanish.
9. The scene in Frenchy's bedroom while Rizzo is singing the line about Elvis was actually filmed the same day that Elvis Presley died.
10. Randal Kleiser hated the opening title song, "Grease" (he thought that the cynical lyrics and disco beat were inappropriate for a film set in the 1950s).
11. The dance contest scene was filmed during the summer, when the school was closed. The gym had no air conditioning and the doors had to be kept closed to control lighting, so the building became stifling hot. On more than one occasion, an extra had to be taken out due to heat related illness.
12. In the scene where the cast are near the bridge after the car race, the water on the ground was stagnant and dangerous. Some cast members became ill from filming as the setting was a derelict place full of dirt and rubbish.
13. The production had a product placement plan with Coca-Cola, but it fell through. The Coke products were taken out or blurred. There is a huge hanging picture/advertisement in the diner that was blurred out. Photos on the inside flaps of the soundtrack album have Pepsi products.
14. Rizzo's hickeys were real. Stockard Channing said in an interview that Jeff Conaway insisted on applying them himself.
15. One of the drummers for the recording session was 'Cubby O'Brien,’ an original Mouseketeer.

And, if that ain’t enough. Here’s a bit of info on slang terms that all "Speed Freaks" should know.

• Balls to the Wall
  Dating back to the 1950's, this refers to an all-out effort. The phrase originated from an aviation term. On airplanes, the throttle control handles and the fuel mixture are often topped with grips that are ball shaped, thus referred to by pilots as "balls." If you push the balls forward close to the front wall of the cockpit your result would be a top speed.
• Drag Race
  "Drag" is a late 18th century term for a wagon or buggy, because the horse would "drag" the wagon. By the mid 1800's streets were the wagons went were called the "main drag". In the 1950's hot rodders started using the term for racing cars on city streets.
• Bat out of Hell (going like a…)

The phrase "Bat out of Hell" can be traced back to the Greek playwright Aristophanes' 414 BC work entitled The Birds.^[19] In it is what is believed to be the first reference to a bat out of Hell.