Here is GM's engine dyno numbers compare for the base C8 LT2 and the much higher costing Z06 with FPC LT6
As you see the LT6 is a slug below about 3,500 RPMs, and giving it gas below that will be slow to respond as torque is 100 ft/lb less than LT2

Above that, the LT6 has no more torque (10 ft/lb less) than the LT2 and only 100 ft/lbs at 2,000 RPMs

HP does not exceed the LT2 until around 5,500 RPMs where most people would rarely see that on public roads.

Makes you wonder what GM is worried about if allowing LT6 more torque overall