410 LA small block will not rev past 6000
If the car has a high stall converter in it, the chassis dyno curve often looks nothing like the engine dyno curve.
For example, if the engine makes peak TQ at 3800, but the converter stall is 4800, the highest TQ number will be at the bottom of the chassis dyno curve……which will start at the stall speed, which is 4800 in this example.
I’ve seen dyno sheets from inertia chassis dynos where the shape of the curve doesn’t even remotely look like engines power curve.