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Engine of the Week

Engine of the Week – 537 cid LS1


527 cid LS1

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Erik Koenig | HorsePower Research McKinney, TX

When it comes to engine size, people never want to go smaller – they only want to go bigger and bigger. Well, those people are in luck. Erik Koenig, the majority owner of HorsePower Research in McKinney, TX, builds the largest LS1 engine in the world at 527 cid.

Koenig got his first taste of the LS platform while at the School of Automotive Machinists (SAM) in Houston as both a student and teacher.

“We did a lot of that stuff there because no one else was doing it,” Koenig says. “We kind of got known, even at the school, for doing the late-model Chevy LS stuff – from the LS1 to the LS7.”


For the last eight or nine years, Koenig has been doing engine work on his own. Last year, he moved up to the Dallas area from Houston and went into business with a few partners to start HorsePower Research (HPR), which is now just over a year old with four full-time employees.

“We do work from plain Jane to ridiculous,” Koenig says. “We do small block and big block Chevys and small block Fords, but LS engines are the shop’s bread and butter.”

This particular 527 LS1 engine wasn’t a customer request – it was one Erik wanted to build – making it the largest displacement for this engine in the world. Only LSX Race Engines Australia (a division of GM Motorsport) has done one as well.


“They’re the only ones I know who have built one like ours, but theirs is one-half cubic inch smaller,” he says. “We do the 527 LS1 engine as race engines, endurance engines, drag engines, and for street cars. People just don’t think you can do it. We have 527s that make more horsepower than blower motors and there’s not a blower. People open the hood and they’re looking for nitrous, but there isn’t any.”

Koenig does admit that while he has built many 527 cid LS1 engines to date, at this level it isn’t an easy build.


“We use our own custom, 6.440˝ steel connecting rod,” he says. “It has an .866˝ pin and it’s a small journal Chevy bottom. The crank is an eight counterweight Sonny Bryant, and it’s made for what we’re doing with it. This crank is the main thing that makes this engine possible.”

The 527 is a naturally aspirated engine. The Wiseco pistons are too short to have a big power adder on them, but according to Koenig, they have a nice low taper and are really lightweight to keep the bob weight down for the balance. In addition, the 527 LS features Total Seal rings and COMP cams.


While this engine has a lot of goodies, the true stars of the 527 are the heads and the manifold if you want to get a lot of power.

Since the 527 engines are so big, even with the best heads in the world, Koenig says they run out of air by about 8,000 rpm. This allows for a lot more lift because of the low rpms and makes a more reliable engine.

The 527 engine uses LS7 heads or bigger because the engine is so large. HPR used Brodix cylinder heads for this build. The 527 LS1 also gets Cometic gaskets.


“On these engines we can only use Cometic because, even with a taller deck, to get our piston right we run the piston way out of the hole and we’ll use real tall head gaskets they make that are like .150˝ tall. They have a built-in aluminum spacer.”

However, it’s the manifold that Koenig says is the main reason why most people don’t build these engines. An incorrect manifold can chop off a lot of horsepower, so they end up being custom.

HPR’s 527 cid LS1 engine cranks out between 650-720 hp at the wheels with a compression ratio around 11.5:1, depending on the application. With a quality manifold this engine can make 750 hp at the wheels. ν


The Engine of the Week eNewsletter is sponsored by Cometic Gasket and Penn Grade Motor Oil.

If you have an engine you would like to highlight in this series, please email Engine Builder magazine’s managing editor, Greg Jones at [email protected]

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