Everything Marisa Tomei Got Right About Cars in 'My Cousin Vinny'

Her character, Mona Lisa Vito, sure knew her cars — but she wasn't quite perfect.

Brett Berk | 

Mar 7, 2024 | 6 min read

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In the 1980s, Marisa Tomei had appeared on the daytime television show "As the World Turns" and the first season of the sitcom "A Different World," but her breakout role — and the one that earned her an Oscar — was in the Joe Pesci movie "My Cousin Vinny."

In that movie, Tomei played Mona Lisa Vito, a smart-talking Brooklynite who is engaged to Pesci's character Vinny, who has recently become a personal-injury lawyer. The plot revolves around the wrongful arrest of Vinny's cousin Bill. In the end, Bill's fate hinges on the vehicle he was driving at the time of the crime and whether it could have left the tire tracks that were found at the scene.

Fortunately for Vinny and Bill, Lisa comes from a family of mechanics — her father, her maternal and paternal grandfathers, four of her uncles, and three of her brothers worked in the trade — and she grew up working in her dad's shop doing tuneups, oil changes, brake jobs, rear-end work, and engine and transmission rebuilds. Vinny puts her on the stand to prove his case, and in her iconic scene, she undoes the case against Bill with her vehicular expertise.

But while she was correct about many details, she was off target on others.

Right: Chevrolet Didn't Make 327-Cubic-Inch Engines in 1955

Ignition timing is the precise moment when a spark is released to help combust the fuel in the cylinder of a gasoline-powered internal-combustion engine, relative to the movement of the piston and crankshaft. The district attorney character tries to undermine Lisa's expertise by asking her a very specific question about the correct ignition timing on a 1955 Chevrolet Bel Air with a 327-cubic-inch engine and a four-barrel carburetor.

Lisa proves her knowledge by replying, correctly, that what he was asking is a trick question. "Chevy didn't make a 327 in '55. The 327 didn't come out till '62," she said. "And it wasn't offered in the Bel Air with the four-barrel carburetor till '64."

Right: A '63 Pontiac Tempest Could Be Confused With a '64 Buick Skylark

As Vinny tries to prove that Bill's car was not the one at the crime scene, he questions Lisa about the color of the vehicle the criminal was driving. She correctly notes that the 1964 Buick Skylark driven by Bill and the getaway vehicle, which she believes to be a 1963 Pontiac Tempest, could easily have been mixed up because they both were produced by General Motors and thus were offered in the same color palette.

"Because both cars were made by GM, were both cars available in metallic mint-green paint?" Vinny asked.

Lisa responded, "They were!"

The '63 Tempest shade was known as Silverleaf Green; the '64 Skylark's color was called Surf Green, and while they're not quite identical, they are very similar grayish-green hues.

Right: There Is a Difference Between Regular and Limited-Slip Differentials

The tire tracks left at the scene have a telltale pattern, one that could have been created — given the position of the car and the nature of the curbed roadway — only if the vehicle that made them had a distinctive type of differential, the geared device that apportions power from the transmission to the driving wheels.

Lisa testified, correctly, that it would require a limited-slip differential, which distributes power equally to both the right and left tires.

Right: The 1964 Skylark Had a Solid-Axle Rear Suspension

The tire tracks at the crime scene remained flat and even despite imperfections in the road. This signaled to Lisa that the car that made them had an independent rear suspension — which allows each wheel on an axle to move up and down of its own accord — instead of a solid-axle suspension, where the motion of the wheels is linked because they're on opposite ends of the same beam. This meant the tracks couldn't have been made by Bill's Buick Skylark, which had a solid-axle rear suspension.

Not Quite Right: The Skylark and Tempest Weren't the Same Size

In her speech on the stand, Lisa claims that the '64 Skylark that Bill was driving had the same body length, height, width, weight, and wheelbase as a 1963 Pontiac Tempest. This is incorrect.

These cars are from two different generations of vehicle and were built on different platforms. The Skylark was built on the new-for-1964 A-body platform, which had a 115-inch wheelbase, while the Tempest was built on the previous generation Y-body, which had a shorter, 112-inch wheelbase.

They also differed significantly in length — the Skylark was 203.5 inches long while the Tempest was 194.5 inches — and weight, with the Skylark weighing in at 3,153 pounds and the Tempest at 2,919 pounds. Though their width and height were quite close — the Skylark measuring 73.6 by 53.9 inches and the Tempest at 74.2 by 53.6 inches — these dimensions were not the same, as Lisa claimed.

Not Quite Right: The '64 Skylark Didn't Have Positraction

Lisa claimed that one of the most distinguishing characteristics of the car that made the tire tracks is that it had to have had a limited-slip differential. According to her logic, this makes it impossible for the tracks to have been produced by Bill's '64 Skylark, because the Buick was not available with a limited-slip differential — which she refers to by the General Motors trademarked name Positraction. She also claims that the '63 Tempest was so equipped.

There are actually two errors here. The Positraction product name was used only by Chevrolet. Pontiac's version was called Safe-T-Track. (The word positraction has since become something of a metonym for such differentials.) It also turns out that the '64 Buick Skylark actually was available with an optional limited-slip differential called the Positive Traction differential.

Not Quite Right: Independent Rear Suspension Was Available on Three, Not Two, Cars

As a final means of proving the innocence of Bill and his '64 Skylark, Lisa claimed that, in the 1960s, there were only two cars made in the U.S. that had Positraction and independent rear suspension and enough power to make those tire marks. She names these correctly as the Chevrolet Corvette and the Pontiac Tempest. But she is incorrect that these were the only two.

The Chevrolet Corvair also had such a suspension setup, was available with Positraction, and with certain engine configurations — such as the potent turbocharged engine — could definitely put its power down with enough force to leave tracks. The writer of the film himself eventually conceded that this was true.

Brett Berk

Brett Berk is a New York City-based writer who covers the intersection of cars and culture: art, architecture, books, fashion, film, politics, television. His writing appears regularly in top-tier automotive and lifestyle publications.