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Topic starter
28/11/2025 8:42 am
1963 Chevrolet Z11
The 1963 Chevrolet Impala Z11 was a special, limited-production car built specifically for factory-backed drag and NASCAR racing. It featured a modified 427 cubic-inch V8 engine and lightweight body panels to maximize performance.
Key Features and Specifications
The Z11 was a Regular Production Option (RPO Z11) that transformed a standard Impala Sport Coupe into a formidable race car. Only about 50 to 57 units were produced, and most went directly to professional racing teams, making them extremely rare today.
- Engine: A special 427 cubic-inch (7.0 L) version of the W-series 409 V8 was used, featuring a longer stroke (3.65 in), a high-rise two-piece aluminum intake manifold, dual Carter AFB four-barrel carburetors, high-compression forged pistons (13.5:1 ratio), and a cowl-induction air intake system.
- Performance: The engine was conservatively factory-rated at 430 horsepower and 575 lb-ft of torque, though actual output was estimated to be over 500 hp in race tune. It could achieve quarter-mile times in the 11-second range and was the first stock car to exceed 120 mph in the quarter-mile.
- Weight Reduction: To enhance its power-to-weight ratio, extensive weight-saving measures were implemented, including aluminum front fenders, hood, bumpers, and inner brackets. The radio, heater, sound-deadening material, and front sway bar were all deleted.
- Drivetrain: All Z11s came equipped with a heavy-duty Borg-Warner T-10 4-speed manual transmission and a strengthened Positraction rear axle with a 4.11:1 gear ratio.
- Collectibility: Due to their rarity and significant racing history, surviving 1963 Chevrolet Impala Z11 models are highly sought-after collector's items, with some examples fetching over half a million dollars at auction.
- https://www.autoevolution.com/news/the-story-of-the-1963-chevrolet-impala-z11-the-meanest-and-rarest-impala-ever-built-168250.html
John Bono
North Jersey
28/11/2025 9:02 am
The ultimate 'sleeper'! Talk about a piece of automotive history! Great choice John!
John Kuvakas and John Bono reacted
28/11/2025 9:30 am
Thanks John. I was aware of the Z11 but not that it was available as a regular production option to the average consumer.. I've always been a fan of the 63 Impala. Another learning experience here on the forum.
Topic starter
28/11/2025 9:46 am
My pleasure Bob.Thanks John. I was aware of the Z11 but not that it was available as a regular production option to the average consumer.. I've always been a fan of the 63 Impala. Another learning experience here on the forum.
John Bono
North Jersey
28/11/2025 11:20 am
Must have been an impressive machine - but wow, how did it manage to lay down that performance on such skinny wheels and tyres?
Be nice to imagine it riding on some chunkier rubber.
Graeme.M. Ogg
London U.K.
Topic starter
28/11/2025 11:43 am
@graeme-ogg The Z11 was delivered with 15" X 5.5" wheels with 6.70 X 15 bias ply tires. It was refitted with larger wheels and tires for the track.
John Bono
North Jersey
28/11/2025 12:06 pm
Yes,i kind of assumed that would be the case. I just couldn't resist playing around, as usual. (Got nothing better to do).
Graeme.M. Ogg
London U.K.
28/11/2025 4:59 pm
Love the way you mix up the choices John. All I can think of is the frustration a current owner of one here in suburban Melbourne would experience with its hopelessly congested roads.
28/11/2025 6:26 pm
It was a monster. I had a friend who knew someone who had one. Apparently, you had to qualify to buy one, and they were only available to certified garages with race teams. On top of that, you really had to know someone at Chevrolet to get one. They were nose-bleed expensive and not suitable for use on the street, definitely a quarter-mile machine. I heard they were hot, loud, and buckboard stiff to ride in. All that being said, I would give my eye teeth to drive one.
John Kuvakas
Warrenton, VA