The continuation of Ford's race-winning speed from Le Mans to last weekend's IMSA race at Watkins Glen has led the sanctioning body to employ a special rule to make short notice Balance of Performance changes.

IMSA made great strides in reducing the rapid fire BoP changes that angered many entrants in its first two seasons, and with the addition of a rule stating BoP alterations could not be made seven days prior to an event, Ford's pace at Watkins Glen was expected to stand pat this weekend at Canadian Tire Motorsport Park.

"Due to the atypical shortage of days between the Watkins Glen and Canadian Tire Motorsport Park Events, IMSA is exercising Article 2.2.2. (language below) to enable a change to the IWSC CTMP Balance of Performance Tables outside the standard notification timeline listed in Attachment 2, Paragraph 2.4. of the IWSC Sporting Regulations and SSR.

"2.2.2. Principal Rule. On occasion, circumstances are presented, either unforeseen or otherwise extraordinary, in which strict application of the rules may not achieve the Purpose. In such rare circumstances, Officials, as a practical matter, may make a determination that is not contemplated by or is inconsistent with the rules. Such determinations are reviewable by the Supervisory Officials. All such determinations are Conclusive, except as provided for in the rules."

IMSA's recognition of the GTM performance imbalance was met by allowing the Corvette C7.Rs to drop 10 kilos (22 pounds) and to increase horsepower and torque by installing air restrictors with a combined 0.4 mm wider opening. A minor increase in fuel capacity (+2L) was also granted to compensate for the increase in consumption.

Like Corvette, Porsche's 911 RSR will also remove 10 kilos (22 pounds), Ferrari's 488 was given a minor fuel capacity increase (+1L), and BMW's M6 received no changes.

Ford's twin-turbo V6 GT went in the opposite direction of Corvette's C7.R. The GTs will race at CTMP with an extra 15 kilos (33 pounds) and have had power and torque taken away with turbo boost reductions from 2000-7200 rpms.

IMSA also made changes to the GT Daytona class on Tuesday. Three models gained weight as Audi's R8 LMS GT3 and Ferrari's 488 GT3 acquired 15 kilos (33 pounds), and Porsche's 911 GT3 R was given 10 kilos (22 pounds).

Practice for IMSA's WeatherTech SportsCar Championship at CTMP starts on Friday.