If you have the speed at 1,000 ft, you can calculate the average breaking G-Force in the last 320 feet.

Example Initial velocity @ 1,000 ft (estimate) 170 MPH
Took time to go from 1,000 feet to 1320 about 1.441 seconds
Average deceleration would have been about -1.1762 G? That seems pretty hard braking, but if he was just 160 MPH at 1,000 ft, that is only -0.5435 G ?

Here is the calculator I found:
https://www.omnicalculator.com/physics/acceleration