508.2.

In every zone other than the in-play zone, and also in the in-play zone before the permanent flips, a flip card has only the normal characteristics of the permanent. Once the flip permanent in the in-play zone is flipped, the normal name, text box, type line, power, and toughness of the flip permanent don't apply and the alternative versions of those characteristics apply instead.

Example: Akki Lavarunner is a nonlegendary creature that flips into a legendary creature named Tok-Tok, Volcano Born. An effect that says "search your library for a legendary card" can't find this flip card. An effect that says "legendary creatures get +2/+2" doesn't affect Akki Lavarunner, but it does affect Tok-Tok.