I've raced a LS1 on street, with 106 Oct + street chip and he had a running start.
You gotta remember, those fbodys are like airplanes, and gbodys are like boxes with wheels.
I'm at high alt so the LS1 didn't run that great, but still had a lot of power (not sure of his mods, but he had a few) I could keep up, but couldn't pass him without a standstill start.