Both Specs of Porsche 963s Get Weight Breaks for Petit Le Mans

Photo: Jordan Lenssen/Porsche

Both specifications of Porsche 963s have been given weight breaks, with the 2025 version fielded by JDC-Miller Motorsports having also been handed a power increase for this weekend’s Motul Petit Le Mans.

Saturday’s IMSA WeatherTech SportsCar Championship title decider at Michelin Raceway Road Atlanta sees weight adjustments for all GTP cars except the Aston Martin Valkyrie, which remains below the homologated baseline of 1030 kg, at 1020 kg.

While the Cadillac V-Series.R has been handed a 9 kg increase, the latest-spec 963s from Porsche Penske Motorsport will be 11 kgs lighter than the last round at Indianapolis Motor Speedway.

It marks a 20 kg swing, in favor of the factory Porsches.

The Battle on the Bricks-winning BMW M Hybrid V8 has also been given additional weight (+10 kg) as well as the Acura ARX-06 (+6 kg), in the Acura’s final scheduled start.

In terms of power, minor tweaks have been given to the Cadillac, BMW and Acuras, with the Aston remaining at the maximum 520 kW power output.

However, the Penske Porsches get a notable 1.7 percent reduction in second-stage power, while the privateer JDC-Miller entry will have 2.1 percent more power at speeds below 230 km/h and a minor 0.02 percent boost at speeds over 240 km/h.

Lamborghinis Weighed Down; Porsche Gets Power Increase in GT Ranks

Both generations of Lamborghini GT3 machinery will be considerably heavier for the ten-hour season finale, in what will mark the final WeatherTech Championship outing for the Huracan GT3 EVO2.

The new-for-2026 Temerario GT3, which is in the GTD Pro title fight following two class wins and a run of three consecutive podiums for Pfaff Motorsports, has been hit with a 11 kg weight increase.

Likewise, the Huracan GT3 EVO2, fielded by Wayne Taylor Racing, will be 13 kg heavier than last time out at The Brickyard.

Along with the Ford Mustang GT3 EVO (+4 kg), which won GTD Pro at Indianapolis, they are the only three GT3 models to have had weight increases.

Six of the 11 eligible cars have had weight breaks, with both the McLaren 720S GT3 Evo (-12 kg) and Aston Martin Vantage GT3 Evo (-10 kg) getting the largest reductions, along with the Ferrari 296 GT3 Evo (-9 kg).

While only getting a 5 kg weight reduction, the Porsche 911 GT3 R Evo notably receives a 5.8 percent first-stage power increase, although will face a 0.9 percent reduction in speeds over 200 km/h.

John Dagys

John Dagys is the founder and Editor-in-Chief of Sportscar365. Dagys spent eight years as a motorsports correspondent for FOXSports.com and SPEED Channel and has contributed to numerous other motorsports publications worldwide. Contact John