The second coming of the Hemi...
The second coming of the Hemi launched in 1964 with the 426ci Hemi engine. In production cars, it was called the Street Hemi and was rated at 425 hp. The Street Hemi was available from 1966 through 1971.
Street Rod Specifics
Certainly, the 426-style Hemi engine is no stranger to the frames of street rods of all makes. And, with its identical exterior dimensions, the new block and engine assembly take up as much space as a vintage Street Hemi. That means cutting holes in the hood sides of some rods or leaving them off altogether. As for fat-fender cars, well, you'd better find an awfully large shoehorn. Also like the original Street Hemi, this modern version is no lightweight-a complete assembly pushes the 900-pound mark. One of the easiest ways to offset its girth is opting for World's aluminum version of the block. It saves more than 160 pounds-and it'll lighten your wallet a bit more, too, over the standard iron block. (See the "The Alloy Options" sidebar on page 128.)
Perhaps the most noteworthy specification of interest to street rodders is the new Hemi block's capability of bolting up either Chrysler or GM transmissions. This makes attaching a popular GM overdrive automatic transmission a no-brainer, with no scrounging for a custom bellhousing adapter. Having a transmission built to handle the Hemi's torque will be the trick.
With its performance legacy in the rodding and drag racing worlds, it's hard to contain the excitement for a new era of Hemi hot rodding. This one promises to take Chrysler's legendary elephant engine to new heights of street performance.
History Of The Hemi
Like so many innovations to burst from Detroit in the years following World War II, Chrysler's first production "Hemi" V-8 had its roots in the war effort. Like other manufacturers, it was pressing light-duty passenger car engines into service in heavy-duty-and just-plain heavy-military vehicles. It was a compromise, at best.
During the war, Chrysler began experimenting with hemispherical cylinder head designs as a way to increase efficiency-pushing more air in and out would boost the power of an engine without the need to increase displacement. The Hemi name is derived from the hemispherical shape of the cylinder head's combustion chambers. The Hemi's design attractiveness to engineers stemmed from the domed chamber's intrinsic ability to support high compression with little worry of detonation, compared to a traditional-and more compact-wedge-type cylinder head.
The efficiency of the Hemi engine led Chrysler engineers to draw up 12- and 16-cylinder designs for tanks and planes, although none were put into production. However, a prototype supercharged V-16 aircraft engine was built and tested in a P-47 Thunderbolt fighter. The engine was inverted-the cylinder "V" pointed down while the crankshaft was on top of the engine. It produced approximately 3,000 hp.
Chrysler introduced its first production vehicles with hemispherical-head V-8 engines for the 1951 model year. The engine was dubbed the "FirePower" V-8 and was standard in the Chrysler New Yorker, Crown Imperial, Imperial, and Saratoga. The FirePower V-8 displaced 331 ci, had a 7.5:1 compression ratio, and was rated at 180 hp-a 45hp jump over the previous year's 324-inch, 135-horse eight-cylinder.
The Hemi configuration of the FirePower V-8 that was available in the '51 Chrysler line gave the company a marketing edge to use against competitors, including Cadillac's ground-breaking overhead-valve V-8 introduced in 1949. Chyrsler's 331ci FirePower V-8 featured the same displacement as the Cadillac V-8, but the Hemi V-8 enjoyed a 20hp advantage over the Caddy.