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Big-Block Chevy: Doomed Dinosaur or Immortal Classic Engine?

Big-Block Chevy: Doomed Dinosaur or Immortal Classic Engine?
By Patrick Hill 27 days ago No comments

Until the LS engine came out in the fall of 1996, getting big power and displacement in a Chevrolet engine meant a big-block over a small-block. Small-blocks at the time were just starting to reliably pass the 400ci mark, but the cost of a big-inch small-block was high. If you were building a serious car, that meant a big-block under the hood. Then when the LS arrived, the sun began to set on the venerable big-block Chevy.


Recently, we were on the phone with a customer who has a big-block Chevy-powered car with large-diameter headers. He was tired of the work involved with removing the starter at least once a year because the headers kept cooking it. A simple fix was one of the more popular thermal barriers from Heatshield Products, the Lava Starter Shield™, and it typically doesn’t require removal of the starter for installation.


Lava Starter Shield wraps around the starter solenoid and Bendix drive to protect them from damaging heat emanating from exhaust headers, which could cause premature failure or increased electrical draw, especially on high-compression engines.


But the exchange with the customer got us thinking about something. Why would anyone want a big-block Chevy these days? With everything the LS series – and even the traditional Gen I small-block – is capable of, a big-block doesn’t seem to make much sense beyond a race car. As smaller, lighter or more efficient engines become capable of making the same power as the big-block, why would you build one?


Out of the box, the 5.7L (348cid) LS1 made 340 horsepower. Factoring in modern standards and power measurements, this made it the most powerful small-block Chevy engine (if you didn’t count the unique LT5 DOCH ZR1 Corvette engine). Within five years, the LS6 was released. Although it was still only a 5.7L, it eventually came from the factory rated at 405 horsepower, matching the specialty LT5 and sharing the undisputed title for most powerful Chevrolet small-block ever built. But this output also put it in the realm of the big-block, a harbinger of things to come.


ABOVE: When the LS7 came out in 2006, it was rated at 505 horsepower. At 7.0L (427cid) it was the same displacement as the old 427 big-block, but in a smaller and much lighter package, while making more power than even that of the legendary L-88 427 big-block.


In a few more years, the LS series saw 425 horsepower, the 6.2L (380 cid) LS3 came out, and the 505 horsepower 7.0L (427cid) LS7 was released in the revived Z06 Corvette, each in a lightweight package with the same compact external dimensions as the original LS1 small-block. And the LS7 hadn’t just entered big-block territory with its displacement; at 505 horsepower, it eclipsed even the legendary LS6 and L88 big-blocks. The sun in the big-block’s sky slipped lower, but was still quite bright, until the first LSX series engines were unveiled. It then went from an afternoon sun shining on the venerable Rat motor to the beginning of an evening sunset on the big-block.


ABOVE: The LS6 454 big-block has been something special in the muscle car world, and was considered the top dog of muscle car factory engines for a long time. Until the LS series hit its stride in the 2000s, the big-block was still the go-to platform for large displacement and high horsepower.


The LSX series used the same basic architecture as the LS series, but with a taller-deck iron block capable of being built to more than 500cid, an extra row of head bolts on each side for increased sealing against higher compression and a tougher block that could be built to make upward of 2,000 horsepower. This was an invasion of the big-block’s territory, but in a much lighter and externally smaller package that could easily fit into just about anything.


Today, the power output of the LS series continues to rise, and fewer big-blocks are being dropped between fenders in favor of the smaller, lighter weight, more efficient LS. But what does this all mean for the big-block Chevy? Will it fade into the background like the W-series engines, becoming a novelty that gets pulled out when someone is feeling nostalgic for the old days? Will it soldier on in ever shrinking sects of racing and street performance? Or, like with LPs, will it see a resurgence as people start looking for something different to set themselves apart from the legions of LS-powered machines at shows, cruises and other events?


Tell us what you think: What is the future of the big-block Chevy?

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