The 'Trans-American Sedan' pro series debuted on March 25th of 1966 as a four-hour prequel to the Sebring 12-hour enduro. It was a series intended for the pony cars such as the Mustang, Plymouth Barracuda, and a slew of small-bore Eurosedan cars that were athletically inclined and could handle the rigors of left and right 'road' racing courses. The following year, in 1967, the competition between the ponycars escalated even further, with GM debuting their Camaro, and Pontiac their Firebird. A Mustang based Mercury Cougar and a new Plymouth Barracuda provided plenty of competition to a very full field. Most major automakers provided factory support and attracted some of the biggest names in racing; the number of races in the series rose from seven to twelve. By the 1969 season, the TransAm Series attracted over 224,000 spectators to 13 events. Factory support continued to increase and so did the competition. The sport prospered until the beginning of the 1970s, as new safety concerns, government regulations, an impending oil embargo, and expensive emissions were detrimental to the industry. The cost to build a competitive racer increased significantly. Most automakers backed out of competition, which meant a serious lack of resources and big name drivers. The glory years of the series were over, but much was still to come.
Trans-Am Rules 1966-1972
The TRANS-AM Championship is now over 30 years old on the sixth major rules format. The latest format began in 1980 and continues without major revisions today. Rules for 1966-1972 are as follows:
The series was born in 1966 with a two-class structure. Over and Under Two Liters. The 0-2 (305 cubic-inch) class was for American built 'pony cars' - while European sports sedans were in the U-2 class. O-2 cars had maximum wheelbase of 116 inches, a minimum weight of 2,800 pounds and a maximum wheel width of eight inches. Both classes were based on FIA Group 1 and 2.
1970 through 1972
The series had its first 'single class' format during these years. The small European sedans were split into their own series in 1980 leaving the American-built pony cars in a single class. The five-liter maximum (305 cubic-inch) displacement was retained while a 3,200 minimum weight was in effect.