Kerouac's daughter Jan's scene in the movie

As you probably know, Jack Kerouac’s only child Jan appeared as an extra in this movie. Her scene happens starting about 11 minutes into the movie in the white-walled café/bar scene that begins with the Cassady/Nolte character tipping over out of his chair. Jan is the girl in the white dress sitting along the wall on the right smoking.

In Jan's book “Trainsong” she wrote in chapter 22, “In September I was offered the job as an extra in Heart Beat, a movie about my father's menage-a-trois with the Cassadys. The Acropolis Cafe was just the place for a beat generation coffeehouse scene: a Greek restaurant in downtown L.A., unchanged since the thirties. My job was to sit at a table where two guys were playing chess: to follow their moves like a cat, and to puff like mad on our Camel straights to produce a thick, smoke-filled atmosphere."

If you watch it on a screen larger than a computer’s, you can see that the two men at the table with her are playing chess — especially in the 3rd and final shot of them at the table.

Also, you can see a photograph of The Acropolis Café at http://www.marmaraisland.org/photo/ confirming that this was the scene in the move that was shot at that location and therefore is Jan in the scene.