The summer of 1992 was a magical time for road racing in North America. Lola’s slimline T92/00 Indy car chassis was revolutionary in its tight packaging, and with Ford’s Cosworth-built 2.65-liter V8 XB engine installed, it gave Penske’s curvy PC21 and Chevy’s B-spec Ilmor 2.65-liter V8 a fight that covered both coasts and plenty of tracks in between.

In IMSA’s GTP series, an epic duel between TWR Jaguar’s Formula 1-grade Cosworth V8-powered XJR-14 chassis and All American Racers’ Toyota-powered Eagle Mk III chassis rivaled its open-wheel counterparts for excitement and raw speed. The XJR-14 destroyed the international World Sports Prototype Championship opposition in 1991 with a design that neutered the opposition, re-wrote the rules for its category, and seemingly spelled doom for GTP entrants when it arrived stateside the following year. AAR’s turbocharged 4-cylinder Mk III Eagle was just as pioneering as the XJR-14, and then some.

By the summer of 1992, the Eagle had been in competition for almost one year, and with a recent increase in power and downforce, Dan Gurney’s defining sports car design was smashing track records on a regular basis.

The story takes an interesting twist when IndyCar and IMSA visited the same track within a matter of weeks and, as the history books captured, an amazing demonstration of unbelievable performance took place.

The CART IndyCar Series’ weekend at Portland International Raceway on June 21 featured the use of PIR’s revised, slower chicane at the end of the pit straight, and in qualifying, Penske’s Emerson Fittipaldi set a new track record with a lap of 1:00.658 in sunny, hot conditions. The Brazilian’s PC21-Chevy edged Michael Andretti’s best of 1:00.746 in his Newman/Haas Racing T92/00-Ford, and the American reckoned he could have gone faster, but ran out of fuel as the session ended.

Similar conditions greeted IMSA when the series arrived for their race at PIR on July 26. The same chicane and 1.95-mile layout was used during the event, but thanks to IMSA’s different qualifying format, GTP drivers were limited to making a single two-lap attempt. IndyCar drivers had the luxury of a longer 30-minute session, multi-lap runs and time to perform adjustments between outings. In IMSA, it was one shot, winner takes all, and no do-overs.

It makes the qualifying performance from AAR’s Juan Fangio II even more impressive considering the Argentine ace broke the GTP lap record—and Fittipaldi’s recent IndyCar record—with a staggering 1:00.354 in his Eagle Mk III. The 0.304 margin of advantage for the Eagle over the best Penske and Lola had to offer was remarkable, and while Indy cars maintained slight advantages at the other tracks they shared with GTPs, fans were treated to a period where American sports cars could legitimately claim to be as fast—if not faster—than their open-wheel rivals.

The head-to-head contest for road course supremacy is, unfortunately, not possible with IMSA’s current prototype formula. 

At Long Beach, the first shared circuit in 2015, IMSA’s Prototype pole time of 1:14.790 set by Wayne Taylor Racing’s Corvette DP was well shy of IndyCar’s pole of 1:06.629 turned by Team Penske’s Helio Castroneves in a Dallara DW12-Chevy.

At 8.1 seconds, the gap is notable, and at Detroit, the pole disparity was similar with 8.6 seconds separating Penske’s Will Power from Action Express Racing’s Christian Fittipaldi in his Corvette DP.

IMSA’s next-generation P2 prototypes should be faster than today’s cars, but it’s unlikely sports car fans will witness anything close to what 1992 delivered.