1970 Chevrolet Chevelle LS6
General Motors lifted its internal ban on engines larger than 400 cubic inches in mid-size cars for 1970, and Chevrolet used the opening to drop the 454 into the Chevelle. The second-generation body, freshened that year with sharper surfacing and a divided shark-nose grille, gained an engine to match its stance.
Two versions of the 454 Turbo-Jet were offered. The LS5 used a hydraulic camshaft and cast-iron intake, rated at 360 hp. The LS6 specified a Winters aluminum intake, 800 cfm Holley four-barrel, solid-lifter camshaft, 11.25:1 compression, and forged internals (rated at 450 hp and 500 lb-ft of torque, with the real output widely believed to exceed the factory claim).
The LS6 required the RPO Z15 SS454 package ($503.45), which added power front disc brakes, heavy-duty rear suspension, dual exhaust with bright tips, wheel-arch moldings, and a blacked-out grille; the LS6 engine itself cost a further $263.30. The cowl induction hood (RPO ZL2) was available across SS models.
The LS6 held the production horsepower title outright over Chrysler’s 426 Hemi (425 hp). Just 4,475 were built, and the configuration was withdrawn after 1970 as emissions requirements tightened.
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