You know, 1.37 doesn't seem that fast for a modded Z06.
At the last NASA race at Road Atlanta (where Johnny O'C did the lap) a Honda Civic turned a 1.38, and an INEX Roadster on street tires turned a 1.41.
Even my little Legends car with a whopping 122 HP and hard street-compound tires turns in the high 1.4x there.
We know Johnny can drive, so either he was stroking it (as the video sort of implies) or the extra power was MIA or not that helpful.
It's an interesting piece of data, since times at that track are easily accessible for comparison reasons.
I'm sure the engine makes the advertised power, but it seems a little disappointing to me that it wasn't faster.
I wonder how a similarly-powered GTM with a little suspension tuning would do.