In the 1970s, Chevrolet made a very rare engine called the LS6 V8. Only 4,663 of these engines were produced. This engine was used in models like the Chevelle, El Camino, and Corvette, and it offered an impressive 450 horsepower and 500 lb-ft of torque. Chevy also planned to create a more powerful version called the LS7, but it never happened due to new government laws and increasing costs.
The Powerful LS6 V8 Engine
Chevrolet continued to create powerful engines in the early 1970s, trying to offer the most powerful cars on the road. For the 1970 model year, they introduced the 454 engine package, mainly featuring the LS5 V8 that produced 360 horsepower and 500 lb-ft of torque. This engine was available in the Chevelle, El Camino, and Corvette.
For an extra $263, the LS6 version of the 454 engine offered even more power, boosting it up to 450 horsepower. The LS6 included lightweight forged aluminum pistons, forged steel connecting rods, and a crankshaft, with a higher compression ratio of 11.25:1.
However, due to its high cost, Chevy only sold 4,475 LS6-equipped vehicles in 1970 and just 188 Corvettes in 1971. This limited production makes the LS6 the rarest Chevrolet engine of the 1970s.
The LS6 and the Rare Performance Cars
After 1970, Chevy stopped making the LS6, leaving the LS5 as the top option for their performance cars. This decision was partly due to new government restrictions aimed at reducing pollution. General Motors, Chevy’s parent company, introduced an 8.5:1 compression limit in 1972, ending the era of powerful muscle cars.
Before discontinuing the LS6, Chevy put it in a few 1971 Corvette models, creating one of the rarest performance cars. Only 188 standard Corvettes received the LS6 engine, and just two of these were the ZR2 model, which included a close-ratio Muncie M22 four-speed manual gearbox, a limited-slip differential, heavy-duty disc brakes, and an F41 performance suspension setup.
Despite its impressive features, the ZR2 was expensive, costing over $7,600, making it one of the rarest and most expensive performance cars of the 1970s.
Chevy had plans for an even more powerful engine, the LS7, which was supposed to be introduced alongside the LS6 in 1970.
The LS7 was designed to be a mix between the ZL1 and LS6 engines, featuring a high compression ratio of 12.25:1, forged high-dome pistons, a competition camshaft, and the ability to use 100 octane fuel. This engine would have produced over 500 horsepower and 600 lb-ft of torque.
However, due to new government regulations, rising fuel, and insurance costs, Chevy decided not to put the LS7 into production cars.
Instead, they sold it as a crate engine, which could be purchased and installed in other vehicles. Some of these engines still appear on auction sites today. In 2023, a preserved LS7 engine sold for $31,500.
Legacy of the LS Engines
The LS engines represent Chevy’s peak in creating powerful engines before government regulations reduced their power after 1972. Today, modern technology has brought back high-capacity V8 engines, like the one in the 2024 Corvette Z06, but the LS engines will always be remembered as some of Chevy’s most powerful creations.
Most readers will understand that the writer meant LS engines of the 70’s meaning MK-IV big block chevy LS-5 and LS-6 RPO codes. Not to be confused with LS engines that came around decades later to replace the Gen 1 SBC.
First car I bought was a 1970 Chevelle SS 454 with a 450HP LS6.
Purchased in 1973 for $ 2400.00 , Ran it at our local drag strip in Stock ET and ran consistently in the low 13s with just a set of Hooker Headers and L-60 Mickey Thompson on the back. Good Times and a Boss Car