Anyone else notice when Potsie arrives at the Cunningham's (at the front door) to stay over, he whispers to Richie that "the drag race starts at 9:00..."

BUT at Arnold's when Skizzy is challenging Ralph he states to meet him at 7:00 at the Airport Row.

Which is it -- 7 or 9?

Well it doesn't really matter anyways because of the following:

Later on in Richie's room when Ralph comes to his window - he notifies Richie and Potsie that the race is changed to midnight!!

Good observation Billy. I noticed changing camera problems when the scene in which Ralph is coming to Ritchie's window. I especially liked the exchanges between the cop (played by Herb Voland) and Mr.C when the latter is in the police station. The Cop says to Mr. C things like "You're starting your own teenage gang".