RE: LR-1 Pylon racer
You might try dropping the diameter of the prop to a 6.5 X 6.5 to lower the amp draw. I might even go so far as to try a 6 X 6. It's either that or switch the battery pack (more parallel cells) or use a motor with slightly less kV. I'd play with props 1st.
Have you any way to measure top speed? When playing with props it's more accurate to use measurements (radar, doppler, or measured and timed course) over the eyeball method.
In respect to the ESC, it harder on them running at part throttle at or near the max rating. If you can use the next higher rated ESC.
BTW, how was your motor and battery heating during the flight? I'll bet the battery was hot but how was the motor?