Certainly is a RPM level that is optimal for a given engine where you maximize performance AND 24 hour longevity and maybe or maybe not 7000 was it for the GT.
If it is a quote from Shelby, maybe that was the RPMs for his (as driver) winning car.
Yep, thats Hollywood, but not something that bothered me. Lots of nitpicky things in movies you can get worked up over. That wasn’t one for me.