Chevrolet
Impala Z11 427

Why it matters

The 1963 Impala Z-11 was a factory race package. It combined the 427 cubic inch 'Mystery Engine' with special Z-11 heads and an aluminium front end and bumpers to cut weight, and was aimed at competition rather than ordinary road use.

How rare is it?

Six separate kinds of rarity – never combined into one number.

Each kind of rarity is rated separately and never combined.

Production

Every figure says what it counts.

Independent counts (e.g. engine and colour) are never combined into a calculated figure. Surviving examples are never presented as original production.

History

The Z11 Impala belongs to Chevrolet's 1963 stock-car effort. Junior Johnson's Impala with the 427 'Mystery Motor' ran 165.183 mph in practice for the 1963 Daytona 500, about eight mph above the previous year's pole speed, and led the race before mechanical problems ended its chance of winning.

Technical specifications

Engine

Transmission & drivetrain

Chassis, body & dimensions

Performance

“Not yet verified” means no source has been checked for that value yet. Nothing is estimated to fill a gap.

Identification guide

How to tell an original from a replica or later conversion.

The conceptcarz profile of a surviving car lists a factory-installed aluminium front end and aluminium bumpers, and the Z-11 package with the 427 cubic inch engine and special Z-11 heads. The profile describes an example that has been through a complete frame-off restoration.

Sources

Each number links to the exact facts it supports.

1. 1
   348-409.com – The 1963 Z-11 427 Impala Level C

   • 57 Z-11 optioned 1963 Impalas produced (commonly cited figure; estimates range 50–57)

   Accessed 2026-11-12
2. 2
   1963 Chevrolet Impala Z11 Coupe (vehicle profile) Level A conceptcarz.com

   • 427 cubic-inch 'Mystery Engine' with special Z-11 heads

   Accessed 2026-11-12