The Chevelle interior has been redesigned for 1970 and the exterior has also been renewed; its now squared up; more symmetrical looking than last year. The sedans are on a 112 inch wheel base and have a curb weight of 3,520 lbs (1,597 kg). There is a full range of models to tempt consumers, but the largest engine option is only offered for the Malibu coupe and Malibu convertible or the El Camino pick-up. The 1970 454 engine is the most powerful ever fitted into the Chevelle, but only for this one year, with the succeeding years offers the performance has been retarded to conform to EPA mandated pollution control regulations.
The best news for 1970 is the latest 454 power option derived from the Mark IV block. The LS6 big block is a 453.96 inch (7.4 L) displacement version on the table for the Chevelle SS this year. This cast iron engine boasts four bolt main caps, forged steel crankshaft and push rods, with the aluminium pistons, also turned out by a forge. The engine was only available as the RPO Z15 SS Equipment option, factory equipped to produce 360 (268 kW) in the base version. The LS6 454 putting out 450 hp (340 kW) is as good as it will ever get for a stock Chevelle. Either one of the 454 engine power options will be equipped with dual exhaust power and could optionally have cowl induction. This ultimate Chevelle engine has a cylinder bore of 4.250 inches (108.0 mm), pistons a 4 inch stroke and the firing chamber has a tight, 8.75:1, compression ratio. The low-rise aluminum intake manifold sports a Holley model 4150, cfm 780 four barrel carburetor, the heads have 2.910” intake valves, and 1.880” exhaust valves, while the extra-beefy dimpled connecting rods are engineered for handling high the high stress of performance driving. The lifters are solid ones and the pulleys are deeply grooved for more efficient power transfer. The ‘70 Chevelle is under rated by Chevy at 450 bhp @ 5,600 rpm and producing a more accurate, 500 lb-ft. of torque @ 3,200 rpm. Field testing done in 1970 strongly indicate well in excess of. 500 bhp, but the figure cannot be backed by any data available now. Super Chevy Magazine did conduct and publish dyno tests on a well-tuned assembly-line produced LS6 engine. The power plant will deliver a peak of 283 hp to the wheels which would equate to about 500 bhp (350 SAE Net Hp) rating. The top speed recorded for a factory produced 454 Chevelle, in 1970, perfectly tuned and equipped with the automatic transmission is 106.76 mph (171.81 km/h). There were 4,475 Chevelle units leave the assembly line in 1970 with the LS6 engine, although only 137 units are officially accounted for and currently on the National Chevelle LS6 registry.