The WeatherTech International Challenge

by   Chris Mulvihill

It was an extremely hot and humid Wisconsin weekend for the mid-summer WeatherTech International Challenge vintage car race.  This year marks the 65th Anniversary season of racing at Road America and featured the 50th Anniversary of the UOP Shadow Can-Am racer.  Over 380 entrants were broken into 12 performance classes providing exciting competition from almost every era of racing.

The new mid-engine 2020 Corvette is the official vehicle of Road America

The early Shadows were designed by Trevor Harris (who later designed the Nissan GTP car) and funded by Don Nichols.  The Shadow’s uniquely shaped low and narrow front end was to increase straightaway speeds.  Unfortunately, this design required small 10” diameter tires which in turn greatly reduced brake shoe size.  Limited braking capability married to a +600HP turbocharged big-block Chevy engine produced unpredictable handling characteristics.  There were also engine and oil cooling issues resulting in limited podium finishes. Later versions of the car worked out some of these issues and the Shadow went on to win the (shortened) 1974 Canadian-American (Can-Am) series.   Their sponsor, Universal Oil Products (UOP) was a petroleum giant that was instrumental in developing the process for refining lead-free gasoline. Legislation was in the works to phase-in lead-free gasoline and “Lead-Free” was painted above the UOP logo. The UOP Company believed this was a way of aquatinting the pubic with lead-free gasoline. 

The large front nostrils channeled air to help cool the Shadow’s undersized brakes

The Can-Am racing series was most popular from its inception in 1966 thru 1974.  The series was very attractive to spectators and participants alike as there were few (if any) horsepower or aerodynamic restrictions.  Combine this with the ability to supercharge or turbocharge the car and you had some machines producing 1,000 HP.

Insert picture (5541) caption “A 1965 Ford GT 40 MKII enters turn 5 at 121MPH-note speed zone sign in upper right corner”

Both Friday and Saturday night of this action-packed weekend featured a concourse held on the start/finish straightaway.  Over 60 competing racecars were displayed Friday night with sports cars filling the straightaway Saturday night.   These were great opportunities for spectators to talk to the owners and get a close up look at some outstanding machines. 

A future racer at the Friday night concourse is ready to pilot this 1972 Austin-Healy Sprite

The Virus has caused the cancelation of many car-related events around the nation.  Road America is a 4.04-mile road course structured to provide one of the most natural settings in the country to watch car racing.  There is enough space for all to roam freely and watch the action unobstructed.  Although the very hot and humid weather combined with the Virus may have kept some spectators away, this weekend was well attended and enjoyed by all. 

About the Author:

Chris Mulvihill founded Classiccaradvisors.com in 2007.  His passion for cars began as a young boy walking the service area of his grandfather’s Oldsmobile dealership. After graduating from Indiana University, his automobile knowledge expanded to the factory side as a Ford Motor Company Field Manager based in Los Angeles.  During his time on the West Coast, he began attending vintage car events where he established deep-rooted friendships in the classic car industry.  His interests are in the history of cars, restoration, and maximizing driving enjoyment.