Although the 1970 Impala looked almost identical to the 1969, certain trims were lacking power under the hood: the 427 engine was a thing of the past along with the "SS" option. Replacing the 427 was a new 454 cid V8 with horsepower ratings of 345 (LS-4) and 390 horsepower (LS-5). Other engines included a 155-horsepower 250 cid six, which was offered only on the four-door sedan and sport coupe in the Impala line as only V8s were offered on the Impala sport sedan (four-door hardtop), Custom Coupe (which shared the squared-off roofline with the flagship Caprice coupe) and convertible, along with the Impala-based Kingswood station wagon. The standard V8 was a 250-horsepower 350 which replaced the 327 of previous years. Optional V8s included a 265-horsepower 400 cid and 300-horsepower 350 cid. The standard transmission was a three-speed manual with column shift and optional transmissions included the two-speed Powerglide and three-speed Turbo Hydra-matic. The four-speed manual transmission was dropped from the option list this year along with the SS package. The 1970 Impala had typical early 70's styling, with an elongated front and roomy cab. Front disc brakes were standard on all Impalas, and were known for their responsiveness and power.
1970 was a transitional year for the Impala; it started to move away from its muscle car roots, and more towards being a luxury family-style car a short step below Chevy's top-line Caprice. Impala remained America's best-selling automobile for the 11th consecutive year.