The big-block Corvette began with the 1965 L78 396, a one-year engine. What followed were nine model years of 427s and 454s, some ordered by thousands of buyers and some by a handful, until the last big-block left the option sheet after 1974. Here are ten of them in order, from the 1966 L72 to the 1974 LS4, with ratings, prices and production counts from the Corvette record.
Each engine went by its Regular Production Option, or RPO, code. That code is how buyers ordered the engine and how the records count it. It also separates a 390-hp cruiser from a 430-hp L88 under a similar hood.
The figures come from the Corvette Action Center, LSX Magazine, the Corvette Report, Hagerty, Over-Drive Magazine and CorvSport. As a result, each item links its source.
1. 1966 L72 427
First, the 1965 L78 396 evolved into the L72 427, the Corvette Report says. Chevrolet introduced the L72 in the fall of 1965 as a 1966 option, LSX Magazine reports. Early 1966 cars carried a 450-hp rating, while later ones said 425 hp.
In fact, the magazine says the only difference was the decal on the air cleaner. Altogether, LSX Magazine counts 5,258 L72 Corvettes.
2. 1967 L36 427/390
Not every 427 was a race motor. For 1967, the L36 was the mild big-block, rated at 390 hp. It cost $200.15, according to the Corvette Action Center’s 1967 production table.
Buyers liked the price, too. As a result, the L36 went into 3,832 Corvettes that year, more than any other 1967 big-block. Total 1967 production was 22,940 cars, so roughly one in six had the L36.
3. 1967 L68 427/400
Then, one step up, sat the L68. The Corvette Action Center lists it as a 427 rated at 400 hp, priced at $305.50.
Still, it found 2,101 buyers in 1967, the same table shows. By comparison, that is about half the L36 total. It filled the gap between the street engine and the 435-hp L71.
4. 1967-1969 L71 427/435
Meanwhile, the L71 was the big number of the era. LSX Magazine describes it as a six-barrel version of the L72, used only in Corvettes. The Corvette Action Center rates it at 435 hp and lists the 1967 option at $437.10.
It also sold well for a top engine. According to LSX Magazine, Chevrolet built 3,754 L71 Corvettes in 1967, 2,898 in 1968 and 2,722 in 1969.
5. 1967-1968 L89 aluminum-head 427
The L89 took the L71 and added aluminum, closed-chamber cylinder heads, LSX Magazine explains. The Corvette Action Center lists it as the “L71 Engine with Aluminum Cylinder Heads,” a $368.65 option in 1967.
Only 16 Corvettes got it that first year, according to the 1967 table. Then, for 1968, the count rose to 624, LSX Magazine reports.
6. 1967-1969 L88 427
The L88 cost far more than the other 1967 options. Chevrolet rated it at 430 hp, and the option cost $947.90. Meanwhile, the 1967, 1968 and some 1969 engines used closed-chamber aluminum heads at 12.5:1 compression.
Also, each car carried a label asking for fuel of at least 103 research octane. According to the Corvette Action Center’s L88 page, Chevrolet built 20 in 1967, 80 in 1968 and 116 in 1969. That makes 216 in all.
7. 1969 ZL1 427
The ZL1 went further than the L88. In short, it was an aluminum-block L88, as Hagerty puts it. LSX Magazine gives the same advertised 430 hp.
However, the price was steep. Hagerty says the engine alone added more than $4,700, more than double the base Corvette. Two ZL1 Corvettes are documented, according to both Hagerty and LSX Magazine, while Chevrolet also built 69 COPO ZL1 Camaros.
8. 1970 LS5 454
For 1970, the big-block grew to 454 cubic inches. The LS5 version carried a factory rating of 390 hp and 500 lb-ft of torque. It cost $289.65, according to Over-Drive Magazine’s 1970 fact sheet.
Chevrolet had planned more, though. LSX Magazine says the LS7 454 never reached production. That left the LS5 as the biggest big-block Corvette of 1970.
9. 1971 LS6 454
Then the LS6 came for 1971. CorvSport says it paired an iron 454 block with aluminum heads, and its spec table lists 11.25:1 compression. LSX Magazine rates the engine at 425 hp gross. The option cost $1,221 and took the total to $6,717, according to CorvSport.
Only 188 LS6 Corvettes left the factory, CorvSport and LSX Magazine agree, plus 12 ZR2 race-package cars. Today, those numbers show in the sale results. For example, CorvSport lists a 1971 LS6 convertible that hammered for $214,500 at Mecum Kissimmee on January 14, 2023.
10. 1973-1974 LS4 454, the last big-block Corvette engine
Finally, the LS4 closed the run. By now the ratings were net figures, and Hagerty lists the LS4 at 270 hp and 380 lb-ft. It used an air injection reactor system to meet emissions rules, and for 1974 it cost $250, less than the $299 L82 350.
Just under 3,500 of the 37,502 buyers in 1974 chose it, Hagerty says, and the Corvette Action Center’s 1974 table puts the count at 3,494. The same site calls the 454 the last big-block in a production Corvette. When Car and Driver tested 1973 LS4 cars, Hagerty notes, the four-speed ran the quarter-mile in 14.6 seconds.
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