440 LSX Bowtie Iron Block Engine Build - Big-Inch LSX

We Build A 440-Inch LS Engine That Puts Out Over 650 HP On 91 Octane.

Unless you've been living under a rock, we're sure you've heard about GM's LS series of engines. When first introduced back in the late '90s, these all-aluminum mills set the Chevy performance world on end and since then it's only gotten better. The 346-inch LS1 begat the 364-cube LS2, which later gave way to the LS3, which displaces 374 ci. The growth spurt came to an end, at least for now, with the 427ci LS7. Sure there were/are other LS-based engines out there stuffed in many of GM's offerings, but none exceed the displacement of the LS7 developed for the Corvette Z06.

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But what if you want more? After all, the term "there's no replacement for displacement" is an often-bantered about cliche for a reason. The LS3 can easily be stroked to 416 cubes and even the expensive and sometimes hard to find LS7 block is ripe for a stroke.

GM Performance Parts saw all this pent-up demand for big displacement small-blocks and decided to introduce an aftermarket offering: the LSX block. The iron block means that it can be bored out to 4.250 inches and it also means it's strong enough for high-compression or boosted applications. Additionally, it offers "race engine" features not found on GM production line blocks. Best of all, at about 2,200 bucks, it's typically less expensive than its hard to find LS7 cousin.

For simplicity sake (or to just tick off the Mopar/Pentastar kids) we decided to build up a 440-inch LS. The 4.125-inch squared-up bore and stroke sounded perfect to us and this wouldn't be pushing the boundaries of the GMPP block, which equates to reliability. We also chose to go naturally aspirated to keep things simple and retain more cash in our pocket. But it's nice to know that the LSX block is capable of handling a little pressure down the line if we decided to go that route and bolt on a blower or add a modest shot of nitrous.

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