Chevrolet's race pace may have come as a surprise to BMW, but not to Corvette Racing as the No. 74 C6 ZR1 continues to lead the GTE Pro class.
The Oliver Gavin/Jan Magnussen/Richard Westbrook car took the lead in the first hour and its rivals have been playing catch-up since.
"Our pace is pretty much where we expected," crew chief Dan Binks said. "We can run it easily.
"We're only double stinting the tires at the moment – we're not taking any chances with the amount of punctures already this year, but maybe if the temperatures drop off to below 49 degrees we'll try a triple stint with the tires.
"It's a fairly linear rate of degradation on the tires and overall, the balance of both cars is good throughout a double stint, but we know there's a long way to go and it's going to be tough."