410 LA small block will not rev past 6000
By the looks of the graph, I would expect it’s pretty easy to determine when the power really drops off while driving the vehicle.
When it reaches the unhappy zone…….look at the tac.
If its a valvetrain problem, by the time it’s really nosed over hard………you’re usually about 3-400rpm past where the issue started.
Edit-I guess this was never really established………
At what point on the graph was the throttle closed, and what rpm was that?
Personally, I hate trying to diagnose potential engine problems from chassis dyno results, especially when there is a high stall converter in the car.