That's a very strange dyno chart: http://sprintexusa.com/wp-content/up...astar_Dyno.pdf

It only goes up to 4460 rpm, and shows the stock engine making peak torque of 243 ft-lbs at 1650 rpm.

I bet that dyno chart is showing calculated brake torque/power (at the engine) based on some assumptions, rather than measured torque/power at the wheels.