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The 1963 Impala SS 409 was fast in its own right, but it was scary fast when equipped with the Z11 racing package that included a 430-hp V8, dual four-barrel carburetors and aluminum body parts.

1963 Chevy Impala Z11 427 & Impala SS409

The 1963 Chevrolets promised Jet-Smooth comfort, Jet-Smooth luxry and Jet-Smooth driving excitement. Then there was the Z11. It went like a jet, but it wasn't exactly smooth as it blasted from the "Christmas tree" and left other super stocks coughing in its dust. The Z11 was a monster and it gobbled up the quarter-mile with brutality, rather that the smooth-sailing of normal street-performance '63 Chevrolet cars.

Chevrolet dropped the Bel Air bubbletop in '63. After that, the Impala coupe with its squared-off roof became the basis for the RPO Z11 drag-racing package. Only about 57 of these cars were built. All were made specifically for Super/Stock drag racing competition. Twenty-five Z11 cars were released by Chevrolet on December 1, 1962. An additional 25 were released on New Year's Day. Seven more were sold later on.

The Z11 option included an aluminum hood, front fenders, fender brackets and other lightweight parts. The cars also had no center bumper backing and bracing. All extra insulation was deleted to cut total weight by about 112 pounds. Under the hood was a 427-cid 430-hp V8 engine with dual four-barrel carbs.

Also in 1963, Chevrolet built five Mark II NASCAR 427 "mystery" engines and used them in racing cars at Daytona Beach. These cars won the two 100-mile preliminary races and set the track's new stock car record. These engines were closely related to the Z11 engines and were prototypes for the 1966 Chevy 396-cid V-8. The cylinder block deck surfaces were angled to parallel the piston domes. The engine also used a staggered, or "porcupine" valve layout. Early in the 1963 model year, General Motors ordered all of its divisions to halt factory support of racing and the mystery-engine project came to a close.

Since most Chevy buyers were not in the market for a Mark II "Mystery" engine or a Z11 package, the best option for those interested in a muscle car for the streets was an Impala SS with the extra-cost 409 V8 engine. The Super Sport equipment package, RPO Z03, was expanded to include all-vinyl bucket seats, swirl-pattern side molding inserts, matching cove inserts, red-filled "SS" overlays for the Impala emblems on the rear fenders, specific full-wheel covers, a center console with a locking storage compartment (with optional PowerGlide or four-speed transmission), swirl-pattern dashboard inserts and an "SS" steering wheel center hub.

The package was again available for the Impala sport coupe ($2,774 with the base V-8 engine). The Turbo-Fire 409 V8 was available in three versions. The mildest one had a single four-barrel carburetor and 10:1 compression ratio. The second one, selling for $424 extra, came with a single four-barrel carburetor, dual exhausts, a high-lift camshaft, solid valve lifters and 11:1 compression ratio. The wilder 425-hp version, for $484 more, had dual four-barrel carburetors, dual exhausts, a high-lift camshaft, solid valve lifters and an 11:1 compression ratio.

Motor Trend technical editor Jim Wright tested two versions of the Impala SS in the car magazine's March, 1963 issue. One had the 327-cid V8, the other had the 409-cid/340-hp engine hooked to a Powerglide two-speed transmission. Even at that, it did 0-to-60 mph in 7.7 seconds and covered the quarter-mile in 15.9 seconds at 88 mph. It was no Z11 but it was fast for 1963!
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