The former open-wheel ace Allmendinger lapped the 3.56-mile course in 1min34.287sec, compared with six-time IndyCar champion Scott Dixon’s 1min34.562sec in the Chip Ganassi Racing Cadillac DPi-V.R.
Another two Cadillacs, those of Kamui Kobayashi (#48 Ally Action Express Racing) and Sebastien Bourdais (JDC Miller Motorsports) were third and fourth fastest – the latter just a hair faster than Jonathan Bomarito in the Mazda RT24-P.
In LMP2, Mikkel Jensen kept PR1/Mathiasen Motorsports at the top of the times with an excellent 1min35.979sec, barely 0.4sec slower than the slowest DPi time.
Jensen was 0.17sec ahead of Matthieu Vaxiviere in the Tower Motorsports by Starworks machine, with Robert Kubica third for High Class Racing.
Dylan Murry’s best effort ensured Riley Motorsports again topped LMP3, this time ahead of the sister car driven by Scott Andrews. Road To Indy rising star Rasmus Lindh was third fastest for Performance Tech Motorsports, a tenth ahead of veteran and former Prototype champion Joao Barbosa in the Sean Creech Motorsports car.
Gianmaria Bruni caused a stir with fastest time in GT Le Mans, driving the new WeatherTech Racing Proton Porsche 911 RSR-19, lapping a tenth faster than James Calado in the Risi Competizione Ferrari 488.
Meanwhile, Antonio Garcia and Tommy Milner kept their Corvettes ahead of the BMWs.
Mirko Bortolotti finished GT Daytona’s portion of the session on top, ahead of a trio of Porsche 911 GT3 Rs – Team TGM (Owen Trinkler), Team Hardpoint EBM (Katherine Legge) and Pfaff Motorsports (Laurens Vanthoor).
The 1hr45min third practice begins at 7.15pm local (Eastern) time.