This clip from “My Cousin Vinny” was posted in the comments recently, and it reminded me that I’ve long wanted to debunk its key element—one that has been held in high esteem by car guys—that the ’63 Pontiac Tempest had a limited slip differential along with independent rear suspension, thus being able to make tire marks that a ’64 Buick Skylark could not have made with its solid rear axle and non-limited slip differential.
Here’s why:
The 1963 Tempest did not offer a limited slip differential as an option; there’s no mention of it in the brochure. Ate Up With Motor sent me more evidence: a factory repair manual for the rear transaxle with lots of details but no mention of an LSD. And then he sent me a Car Life review of a ’63 Tempest with the V8, and it clearly states that the car struggled with traction and that a limited slip differential was not available.
Meanwhile, contrary to Lisa’s assertion, a limited slip differential called “Positive Traction” was available on the ’64 Buick Skylark. Neither Pontiac or Buick were allowed to use the term “Positraction” as that belonged to was Chevy.
The other mistake is that she says that the ’63 Tempest and ’64 Skylark had the same wheelbase; wrong. The ’63 Tempest’s was 112″ and the new larger 1964 GM A-Bodies all had a 115″ wheelbase.
For that matter, the ’63 Tempest (top) and ’64 Skylark are of two totally different generation of cars, and they don’t really look all that similar. All the dimensions are different, as well as how they look. As to the “Metallic Mint Green” paint they both allegedly have, I see two greens that are somewhat similar, but don’t look the same to me. But maybe someone has better eyes than mine.
Marisa Tomei gave a great and convincing performance that won her an Oscar, but it was all BS. Which of course is utterly appropriate for making the men all look dumb. As well as for making a great movie scene.
Now you just said there’s no Santa Clause ! boo woo ! lol But what a great movie !! but being a old time mechanic & if the tech book says so well you can’t argue with the book ! sooooooooooo
One of our favorite movies. Tomei was great!
Thanks for this, Paul… it did seem a bit unlikely. I always though the wheelbase was off, but the track was what mattered, and I suspect it was not the same either.
“Marisa Tomei gave a great and convincing performance that won her an Oscar, but it was all BS.” (This error shouldn’t cause loss of her Oscar… unlike a Nobel and a couple of Pulitzers that really should be retrieved!)
My Dad will be broken hearted to see this! This is probably his favorite scene from his favorite movie…
Drivetrains aside, there is another problem with Marissa’s testimony here.
The 1963 Pontiac Tempest and the 1964 Buick Skylark were of two different generations…heck, maybe even different platforms…
Didn’t the ’63 Tempest have that “Rope-Drive” affair? Also, I would think that these two cars look significantly different enough not to be confused.
I learned all this stuff right here at CC! – Unless in my old age, I am misremembering all of this. LOL .😂
Of course the witness to the getaway car may not be a car person, but all of this does speak to reasonable doubt. Perhaps we should let our house attorney JPC chime in here. JPC, what say you?
You are not misremembering- these two cars have not a single nut or bolt in common.
I’m not sure I’d go quite that far, but yes, they are essentially totally different cars.
I drove my family’s 65 Buick Special convertible through a scene on the movie Boston Strangler, released March 2023 on Hulu. I drove it through a scene that took place in 1962. I mentioned to the director that the 65 body style came out for 64 and could possibly be in a scene from late 63, with the 65 playing the part of a 64. He thought I was crazy and said “it’s an old car. Close enough. Nobody cares”. Well “WE” care. See see it. That 62 scene didn’t make it into the movie. But they did use another scene where I drove our car in one direction on a country road while the lead actresses stunt double drove her Ford Falcon in the another direction. Then they digitally changed the color of our car from bright burgundy red to this greenish black, so that it didn’t overshadow the Falcon. Now here is a point relating to the current actors strike. I signed a contract for this car to be driven in that movie at that time. Although only one of three scenes filmed made it into the movie, they have all three on film. So the studios think they have the right to digitally insert our car in any movie in any way they want. They never need to film a 65 Buick Special again. They will never pay me to drive again. This is just wrong.
A friend of mine once had a ’54 Cadillac sedan in excellent condition bought from an elderly gent who babied it over the years he owned it. To seal the deal, my friend assured him he would take good care of it.
When the Godfather II movie was in production, my friend rented it out to the film production crew for the Tahoe shooting. The car was white when it went out, but when my friend picked it up after the end of the filming, he was shocked to find out that the body below the beltline had been painted a metallic grey. And not very precisely done, nor was it done with any permission given.
When I lived in Toronto my next door neighbour did special effects for movies. I once asked him about renting my car for a movie shoot. His advice was DON’T, but if you do make sure that you drive the car and never leave it alone.
Interesting as heck, Rick. Appreciate the insight. Looks like a nice car, too.
This is a crushing rebuke of one of my favorite movie scenes.
But, be that as it may, I’m still in love with Mona Lisa Vito.
Having owned a ’62 Tempest, when I first saw that movie, I right away figured the rear suspension difference between the two cars would figure into the eventual verdict. It was my first car, first owned by my grandparents who first gave it to my older brothers who weren’t interested in it and so it ended up with me.
What a horrible story Stuart. Some cars in the movie were supplies by companies. Some were lined by owners who were not there. Some, like ours, had the owner on site. That the only way we would do it.
Here is the real car, before they digitally altered the color.
What was the tire – Michelin XGV size 14 (or was it 15)?
Metallic Mint Green paint! Love it!
My partner cracks me up! Loves the scene about the 327 in the 57 Belair and mentions it every so often. Has no clue about cars!
All this talk about the two GM Models and your ignoring the dirty window, rusty screen, Tree, leaves, and seven bushes
Regarding the last point about how the two cars don’t really look all that much alike. That’s true to a certain extent, but remember earlier in the film during his cross examination Vinny demonstrated that none of the witnesses really got a good look at the car (or the defendants). So all they really know is that they saw an older, light green, smallish two door sedan arrive at the convenience store, and later they say an older, light green, smallish two door sedan leave.
Edit: I see Lawrence Copley made more or less the same point while I was typing my comment.
beat both of us to it haha. Totally agree, plus both cars were convertibles, that takes away a big distinguishing feature of the two cars
I’ll give two passes to the movie
– Posi is basically kleenix for limited slips, it’s remarkable how many Mustang owners I know who don’t know their car has a Traction lock differential but will proudly proclaim it has a posi. Marisa Tomei’s character knew a lot about cars but was also very street, so I’ll give positraction an easy pass, it’s all the same anyway.
– The styling of the two cars being different. Remember the movie was set in the then present(1992). If today your average non-car person witnessed a silver 1994 Camry with indiana plates fleeing the scene what would be the description? Probably “silver late model sedan with indiana plates”, that’s often the vaguery you see in news reports when they say “be on the lookout for”, so a 28 or 29 year old intermediate GM convertible, pre internet at that, is seen fleeing a murder by a witness, and the police pick up an old intermediate GM convertible in the same color in the same town it’s not a far stretch to understand the mistaken identity. I believe she had that conclusion, sort of confirmed in saying no one would mistake one of those cars for the Corvette.
The lack of limited slip availability on Tempests is a rough one though.
And of course, nobody knows that the “Posi Traction” was actually an innovation from Studebaker-Packard Corp. and first offered in 1956 model cars (and even in Studebaker trucks later in the model year). From what I have read, the rest of the industry paid license fees for S-P’s “Twin Traction” design and were then able to offer LSDs under a variety of other names starting in 1957.
The limited slip differential was invented and patented by Ray F. Thornton, called the “Thornton Powr-Lok”. The patent was picked up and developed into a commercial product by Dana, called the Dana Powr-Lok. A number of companies then bought the Dana Powr-Lok, Studebaker-Packard being the first in 1956 and then Chevrolet in 1957 and then a rapidly increasing number of other brands. They are all essentially the same product and components, and they all bought it from Dana. I can’t remotely imagine why any license fees would have been paid to S-P.
The reality is that many innovations in the industry that the car makers try to take credit for originated with individual inventors or the many suppliers. Since S-P didn’t build their rear axles and differentials, it rather stands to reason that they wouldn’t likely be trying to invent something totally new in that field.
Here’s the link to Thornton’s patent:
https://patents.google.com/patent/US2971404A/en
Here’s an article on the Dana Powr-Lok:
https://www.hemmings.com/stories/2021/06/10/inside-the-dana-spicer-powr-lok-limited-slip-differential
This makes a lot more sense than anything I had read on the subject before. I remember once trying to get below the “Chevy invented the posi” myth and clearly did not get far enough. For something as historically important as the limited slip, there is not much written on the topic.
> I can’t remotely imagine why any license fees would have been paid to S-P.
Only if S-P had an exclusivity contract with Dana the gave them two or three years before other companies could use it. Kind of like how iPhones were locked to AT&T’s network the first few years.
Only if S-P had an exclusivity contract with Dana the gave them two or three years before other companies could use it.
They didn’t. I did quite a bit of digging on this subject. That’s why I said what I said.
Studebaker would have had to pay a high price to get exclusivity from a large supplier like Dana. That’s something they couldn’t have justified with their low volumes.
The analogy to the iPhone and ATT doesn’t quite work. The only reason they had an exclusive for a few years is because Cingular, which ATT bought, was the only cell company willing to make the major technical changes to their system to accommodate the iPhone, which took up much more bandwidth. No other company was willing to take the risk.
Surprising that limited slip was not available on Tempest when it was an option on Corvair, which didn’t really need it. They shared a lot of driveline stuff.
I’ve watched far too many cop shows, and witnesses are vague or clueless about getaway cars 99% of the time. Some enterprising coder should come up with Identi-kit software for autos, since there are now so many makes and models (and years) on the road. Start with taillight shapes for nighttime IDs. It may all be pointless, however, because “snitches get stitches” in high-crime neighborhoods.
Next, you’re going to tell me the Star Wars movies are not factual. (Scene from 1978’s Hardware Wars)
Well, another bubble in my life has been burst.
All I can add is to confirm that the 63 Tempest and the 64 Skylark did used two different paint colors. There was a 1962-63 color (code WA2978) which Pontiac called Silverleaf Green and Buick called Willow Mist. Then there was a 1964 color (code WA335) that was called Pinehurst Green on Pontiacs and Surf Green on Buicks. In the fictitious witness’ defense, they were similar light metallic greens, and could easily be mixed up by most people (including me).
I’ve rented my Skylark out twice, no issues. First was Young Rock, other production was Tiger King.
If you noticed a white over Signal Red ’69, that’s my claim to fame.
No issues with the production, and I’m pleased to say the ‘lark behaved itself.
This is what keeps me coming to CC, movies and stories are fun, but its great to have this site for the facts you can rely on. A huge thank you to all.
I always thought that this movie was more accurate than most when it came to automotive facts, but it’s still Hollywood, so I knew it was not 100% correct as that never happens. It does apparently have a reputation as being one of the most legally accurate movies. While the lack of availability of posi, sorry, limited slip differential, is a problem, there is one more big issue relating to the rear differential. These are 30 year old cars in the movie, they very easily could have been modified from stock. A simpler test would have been to check the 1964 Skylark in question to see if it was actually equipped with an open differential or a limited slip.
Along with the axle errors, and obvious dimensional differences between the Pontiac and Buick with Tomei claims are identical, Tomei made another error in her testimony. When the prosecutor tests her automotive knowledge by asking for the ignition timing on a 1955 Bel Air with a 327 4bbl, she states that Chevrolet didn’t offer the 327 until 1962 (correct), and that the 327-4bbl wasn’t available in the Bel Air until 1964 (incorrect) and that the timing for a 1964 327 4-bbl would be 4 degrees BTDC (half correct).
The 327 was only available with a 4-bbl carburetor in Chevrolet cars from 1962-1966. The Chevrolet Bel Air could be ordered with a 327-4bbl from 1962-1968, with no 327-2bbl offered. Other than trucks, the first 327-2bbl was introduced to the Camaro line in 1967. It wasn’t until 1969 that Standard Chevrolet line, including the Bel Air, had a 327-2bbl available, It was also during this model year that the 327-4bbl was dropped and replaced with the 350-4bbl. As for the ignition timing on a 327-4bbl in 1964, it was 4 degrees BTDC if it was the 250 hp L30 engine. However, if it was the 300 hp L74, then it was 8 degrees.
I agree with Matt on giving the movie a pass for using “posi” as a generic term for limited slip differential. I also agree that despite the dimensional differences between the 1963 Tempest and 1964 Skylark that are obvious to a CCer, a general citizen looking at a almost 30 year old convertible form a distance could easily mistake one for the other. So that to me is plausible.
FWIW, I tried to point out some of these errors on the IMDB site some time ago. My comments were flagged as not factual errors and not accepted by IMDB!
Darn – another bubble burst.
Despite working at a Ford agency, we did see quite a few GM cars in our shop. Just not enough of them to really become familiar with the subtle differences between the years and makes. I remember that movie and never picked up on the fact the Tempest didn’t over a limited slip diff.
Great comments. The reality is that WE ALL LOVE THE MOVIE. For those of us growing up in New York at that time, DIS IZ DA TROOT!
I was a yout when this movie came out. I loved that scene.
He didn’t claim to be a car person (other than owning a car) but Robin Williams seemed to use his right hand to shift his car into reverse in the movie “Awakenings”, as if it had a regular column shift…but I think he was driving a ’64 Dodge Polara which would have been the last year with push button shift…and it was mounted on the left side of the column rather than the right, and of course the arm motion to move a column shift would be different than pushing button on the dash. Still wonder how they did that…he did actually drive the car in reverse…maybe it was a “doctored” car?
If he had a car even one year newer then it would have been fine…the movie takes place in 1969, so that would also have worked.
As for “My Cousin Vinny” my great Aunt had a ’62 Olds F85 which probably had the shorter wheelbase (she got a ’69 98 and gave the F85 to my Uncle). My Dad bought a ’65 F85 wagon with the longer wheelbase (and the 330…his first V8).
With two different cars. From inside the car we see him get into an automatic ’64 Dodge. Transmission pushbuttons are in a vertical row at the left side of the dash. Then as he turns the key (at least they had the grace to use the correct starter sound!) the camera angle changes; now we’re outside the driver’s door and we see him move an actual, real 3-on-the-tree shift stick into the rearward-upward position, which is Reverse. Then we hear the sound of a manual-transmission car reversing. And then, a few seconds later, we see the shift stick through the windshield and it’s a ’66-up lever and knob, even though the car is clearly still a ’64. It’s bugged me for years. This is a recording.
This seems like one of those “2 plus 2 must equal 4” situations, i.e., if the Corvair had an available limited slip differential, and the Tempest used the exact same rear transaxle, then the Tempest surely must have had the Corvair’s same limitied slip option. Unfortunately, that doesn’t appear to have been the case.
What I’m wondering is if whomever did the technical research for the movie knew it, and just went with the storyline, anyway, figuring no one would know (or even care) about the error.
I have to admit that it does seem strange that there was a limited slip option on the Tempest, particularly since there ‘was’ the option on the Corvair’s identical transaxle.
It’s all quite a bit of esoterica, and I’m glad for the correction of a very popular scene in a very popular movie.
What I’m wondering is if whomever did the technical research for the movie knew it, and just went with the storyline, anyway, figuring no one would know (or even care) about the error.
That is the $64k question. My guess is that someone knew enough about cars of this vintage to write the story lines, but they probably didn’t know the fine details. That’s also evident in the line of questioning about the 327 in the Bel Air. Her answers are close, but there’s some gaps as Vince has pointed out in his comment further up.
The Tempest’s transaxle wasn’t identical to the Corvair’s. It was based on it, but there were differences too. My guess is that the Tempest needed a tougher differential to handle the V8s, and that’s why the Corvair unit didn’t fit.
That’s probably what happened, given the lines about “size 75R14” tires—which means nothing as stated, and less than nothing in context of reading tire prints on a road.
I love that ice blue Skylark ! .
-Nate
I ordered and bought a 1963 Pontiac Tempest Lemans 326 HO in March of 63. It was special ordered with a 3 speed floor shift and a 3:56 Postitraction Rear End. The Ho engine came with a 4 barrel carb and dual exhaust with a higher compression ratio than the standard 2 barrel 326. It was rated at 280 hp. So for all the experts out there it did have POSITRACTION. The car was quite fast for the time and I surprised many so called performance cars back in the day.
Suuuurrrreee you did. “special ordered” even though Saf-T-Track was NOT an option on the ’63 Tempest nor was a “326 HO”, the only 4bbl offered was on the Trophy 4. A 3 speed and 3:56 ratio were the only facts you have right.
https://www.curbsideclassic.com/vintage-reviews/vintage-car-life-road-test-1963-pontiac-tempest-lemans-326-v8-the-warmup-act-for-the-gto/
Here’s a recent article from this website: It mentions the 326 HO (with a four-barrel carburetor and 280 hp) as being a late-release option in 1963 that Car Life tested.