Learn about Jay Leno and the history of transom racing.

The SCCA Trans-Am series achieved iconic status in the late 1960s and early 1970s. In this episode of "Jay Leno's Garage," Jay Leno, NASCAR commentator Mike Joy, and historic racer Ken Epsman take a look at some of the cars that made that era of transom racing so special. Along the way, they will also learn about the history of transom racing.

The SCCA launched the Trans Am in 1966 in an effort to develop a professional series beyond amateur racing. The Trans Am series consists of two classes: one with engine displacements of less than 2.0 liters, and one with engine displacements greater than 2.0 liters but capped at 5.0 liters or 305 cubic inches.

The latter created an opening for Ford, General Motors, Chrysler, and AMC to introduce pony cars that were just beginning to hit the market at the time. The Ford Mustang, Chevrolet Camaro, Dodge Challenger, Plymouth 'Cuda, and AMC Javelin all competed in the Trans Am series with factory support during this golden era that lasted until 1972. Later, the rules were changed and the Trans Am moved from a production car-based formula.

The Pontiac Firebird Trans Am is missing from this list. It was named after the series, but could not compete because its engine exceeded the maximum displacement of 5.0 liters as required by regulations. Even though the Firebird did not have as consistent factory support as the Camaro, it did compete in the Trans Am, and GM paid the SCCA $5.00 for each Firebird Trans Am road car sold GM paid the SCCA $5.00 for each Firebird Trans Am road car sold paid SCCA $5.00 for each Firebird Trans Am road car sold.

What set the Trans Am race car apart was its similarity to the road car. Under the original rules, the bodyshell and powertrain had to be stock, which made racing interesting and spawned classic homologation specials like the Ford Mustang Boss 302 and Chevrolet Camaro Z/28. These cars were raced by famous drivers such as Dan Gurney and Mark Donohue, and the Trans Am series created a bigger buzz than NASCAR, which at the time was still only popular in the South, according to Joy.

Because of this rule, for example, the Ford Mustang's huge oil sump (since dry sumps were illegal) and the 1970 Camaro racer's use of a base front fascia instead of a fancier rally sport version to save weight forced some interesting workarounds. Not everything was stock, as the Camaro used a Chevrolet Impala rear axle to increase track width, but at least the car looked the part.

At a time when "win on Sunday, sell on Monday" was still a credible strategy, the Trans Am became an important marketing tool for automakers. In particular, AMC partnered with Kaplan Engineering, Penske Racing, and the Roy Woods team to promote the Javelin as an alternative to the Detroit Three Pony Car. This effort won titles in 1971 and 1972 and brought brief glories to AMC and Javelin.

The video, like most of Leno's videos, ends with a drive in one of the cars. In this case, it's Jim Whelan's originally raced No. 89 1966 Ford Mustang, and we can't wait to hear the GT40-head-equipped 289 in action on the street.

The Trans Am series still exists today, but the race cars have little in common with road cars and have been overshadowed by NASCAR, F1, IndyCar, and IMSA racing in the US. However, the cars from 1966 to 1972 are still iconic.