Chevrolet Impala SS
At the dawn of the 1960's, Kennedy, the new President-elect, spoke of a "new frontier." He was talking of new age of post-war prosperity and specifically, America's quest for reaching the Moon. For the big three, the new frontier was one of technical and marketing innovations. Combining the two became an essential element in the rapidly maturing market.
Marketing scored with the invention of youth-oriented cars such as the Mustang and Barracuda. The engineers scored with thin wall casting and improved reciprocating assemblies from the rotating valve lifter to the use of Teflon buttons in pistons to prevent scuffing. When good engineering and marketing combine, the effect is shattering. The Impala SS of the 1960's was an excellent example.
The Impala had become the top model in '59, replacing Bel-Air's position. In '58, Impala was a top of the line Bel-Air. Over the years, it had grown in wheelbase from 115 inches to 119 inches. The far out styling was immediately toned down for 1960. A new package had been developed in 1961 to help secure Chevy's sales' dominance in the full-size arena. It was called the Super Sport, or SS, for short.
It was a complete deal, comprising of exterior badges against the Impala crest on the quarter panels, bucket seats, floor shift trim plate, a steering mounted tachometer, a passenger dash grab handle, special trim and a modified LPO 111 suspension package, power steering, power brakes, and wheel covers. The origins of this package came from a show car.
The 1961 SS Impalas weren't standardized in appearance. You could order the package on a four-door car, a six-cylinder powered coupe or you could go "top drawer" and get a slant back sports-roof with the hot 348 engine. It was basically a sales code without formal restrictions, although that would change soon enough.
Chevy had great options available in short runs, but no easy 1-step option that gave you the basics to go racing. The 1961 SS Impala changed all that. Previously, there were the Fuel Injected Ramjet and Ramjet Special 283's, but they vanished by the end of '59. Likewise, you could get LPO 1108, which was a heavy-duty suspension for Police Cars. This gave you metallic brakes, H.D. ball joints, bigger shocks, stiffer springs and better wheel bearings front and back. Available on every model, but certainly not advertised!
The sales of four speed cars had sky rocketed sharply in 1961, guaranteeing the future of the SS. New for '62 was a full-length console. The fancy wheel covers were a necessity, the slots helped cool down the brakes. What did change were the engines. The 409 was about to have its fifteen minutes of infamy. The 409 has been a controversial engine. Denigrators call it a truck engine. Fans call it the early sixty's track god. It was a little of both as we'll see.
Starting with the 348 block, Chevrolet changed much of the hardware to create a racing engine to compete against the Ford 390 Interceptor from 1960. The crankshaft was forged, as were the aluminum pistons. A performance solid-lifter cam, raised compression to 11.25:1 and used a Carter AFB carburetor on an aluminum manifold. It made 360 horsepower @ 5800 rpm and torque was a legendary 409 lbs.-ft @ 3600 rpm. A real brute of a motor.
The cylinder heads were different from the 348's and used stiffer springs and heavy-duty pushrods. Nineteen sixty-one SS Impalas were scarce with only 453 made. As for an SS 409, you'd have better luck meeting Elvis because only 142 made it. The transmissions were either Powerglide, Warner T-10 or the three-speed standard.
Nineteen sixty-two brought the SS Impala package onboard and the 409 was more obtainable. Those eager beavers that placed orders for early 62's must have been annoyed when Chevy announced a dual-quad 409. At least the four-barrel engine had been improved with power up to 380 horses. The dual-quad engine put out 409 horses @ 6000 rpm. A hair more than 15,000 units sold that year. As the drag-strip wars heated up, Chevy brought out special aluminum front end Impalas. But there was no official racing going on, just some "off-road" and "fleet service" parts being sold over the counter.
Nineteen sixty-three brought a facelift to the grille and side panels with two chrome blocks on the fenders and a lower spear resting above the rear wheel well. The badges moved from above the bumper to behind the front wheel. The beautiful spinner hubcaps changed to a variation of the 1961 Impala model with the SS logo prominently displayed. New that year was the detuned 409 mill @ 340 horsepower. A 400 horse 409 existed midway through the range with solid lifters and the dual-quad 425-horsepower 409 had a lower 11:1 compression ratio.
Still, Chevy hadn't gone soft on us. The Z-11 was the latest doomsday machine and was a 430-horse version with the displacement at 427 CID. Strictly for drag racing, these cars were sold to connected guys such as Dave Strickler and Hayden Profitt.
Nineteen sixty-four was the final year of this body style Impala. For the last go-round, Chevy gave us better rear end choices with our four-gear cars and a sharp-edged car that attempted to emulate the new thin gauged sheet metal cars with uni-bodies like the Chryslers and smaller GM offerings that year. Engine-wise, there wasn't anything new to report. Let's clear up the misconceptions about 409 engines. First, it is related to the 348 W motor of the late '50s in that the block casting started out the same. Pretty soon afterwards, the 409 developed a life of its own. From the start, it was intended to replace the 348 and provide more power for bigger bodied cars. 348's were used frequently in trucks and their outward similarity probably made people conclude the 409 was the same. In fact, the early 1961 four-barrel mills seemed pretty tame.
Demand was strong for this motor so the early 1962 409 was unchanged from last year spec wise. You got a cam with 0.440 lift and 317/301 duration with dual point ignition. These early distributors had no vacuum advance provisions.Later in '62, the dual-quad was improved. This engine had increased airflow, better cam specs with 0.480 lift and 322/320 duration. The ignition was switched to single points.
Allowing use of vacuum advance on this engine. Head gaskets were used to change the compression ratios. Two gaskets per head yielded 10.2:1. For hotter competition, one was removed each side to give 11.04:1. By altering gasket arrangements, compression ratios could go up to 11.4:1. Regarding block identification, there are a few variations you should be aware of.
The early '61 409 block had casting number 3795623. The '61 to '62 solid cam engines used number 3788068. The 1962 to '63 block employed number 3839752 while 3860386 was for 1962 to 1964 blocks. The '64 solid cam block used 3844422 number and the fabled Z-11 mill was casting 3830814. One block to avoid for proper resto purposes is 3798962, a juice cammed truck engine.
Cylinder head castings are numerous; the early '61 castings were 3795586, the hi-perf '62s and 63's are 3814690, the 1963 std head was 3830817 and the RPO- Z11 head was 383 7731. There was also a 3852583 casting for 1964 hi-perf along with the std head from '63. Truck heads are recognized as 3819353.
Intake manifolds are expensive and a plethora of them exist. 3844463 is the steel 1x4 manifold used in 1961 and 1964 engines. A 1962 version has numbers 3814678 and was aluminum. It was also used in '63. A service replacement carried numbers 3822928. The dual quad manifold was 3814881 while the Rochester 4-barrel versions were 3794129 and 3830831 for 1963. An aluminum 1x4 manifold came out as 3814678 in '63. The Z-11 manifold was two pieces, the top one was 3830623, the bottom was 3830733.
By 1963, Chevy knew they had a winner deserving of a special reward. The upcoming 50-millionth Chevy was rapidly due to be assembled in Tarrytown, New York. The powers that be made sure car 50,000 000 was an SS 409 Impala. A whole promotional blitz ensued with New York Governor Nelson Rockefeller driving that car off the line while GM brass watched. The car was a four-barrel sports coupe with special-order paint code 927. This was a 1962 color called anniversary gold used previously to commemorate Chevy's 50th year in business.
Though it was late in the year, GM had released a small run of replica cars in that color. With 13 Chevy plants, it was possible that their goal of 7000 special cars made it. The 50 millionth car was made June 10 and has survived in immaculate condition from deep storage. It was a grand gesture to celebrate a great muscle car. The 409 passed the torch of fame and power to the 396 engine as the decade passed.