How Does an LS7 Look After 86,000 Miles?

Minus one small issue, these LS7 engines are built for the long haul.

The LS7 is one of our favorite LS variants of all time. The aluminum 7.0 liter LS7 V8 is factory rated at 505 horsepower, making it the most powerful normally aspirated LS engine ever put into a production vehicle. It originally debuted in the C6 Corvette Z06, where “505 HP” was proudly called out on the emblem itself.

As you can imagine, a hand-built engine like this is built for high performance, which usually means it’s here for a good time, not a long time. However, you may change that stereotype after seeing this video from Jacob Villemain, also known as That Engine Guy on YouTube. In the video, he tears apart an 86,000 mile LS7 on camera.

Being derived from the legendary Corvette C5R racing engine, the LS7 utilizes some heavy-duty race-bred components. These features include a dry sump oiling system, titanium connecting rods, CNC ported heads, and a forged crankshaft. While most of these details serve to make the engine perform better, a few pull double duty as durability upgrades.

Almost As Good As New

After showing off the extra-tough billet steel main bearing caps, Villemain measures the main bearing clearances of this well-used LS7. Surprisingly, the tolerances are still tight – just two thousandths of an inch (0.002″). Not bad! This engine likely could have survived many more thousands of miles in stock form.

The camshaft shows a wear pattern, but according to Villemain, you can’t actually feel it – it’s strictly a visual indicator. The camshaft is good to go for thousands more miles. Similarly, the balancing weights pressed into the crankshaft haven’t budged a bit since this engine was originally assembled nearly twenty years ago. There’s some carbon buildup visible on the cylinder heads, but it would clean up fairly easily.

Now, there’s been a lot of talk about catastrophic failure of these engines due to dropped exhaust valves. Specifically, the valve guides wear too quickly, which can eventually cause the exhaust valve head to snap off of the stem. The exhaust valves looked good on this engine, but the exhaust valve guide clearance was dangerously excessive at .0039″. It’s clear that these LS7 engines can be very robust, but these valve guides are an Achilles heel. These should be addressed on any LS7 build.

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Cam Vanderhorst

Cam VanDerHorst has been a contributor to Internet Brands' Auto Group sites for over three years, with his byline appearing on Ford Truck Enthusiasts, Corvette Forum, JK Forum, and Harley-Davidson Forums, among others. In that time, he's also contributed to Autoweek, The Drive, and Scale Auto Magazine.
He bought his first car at age 14 -- a 1978 Ford Mustang II -- and since then he’s amassed an impressive and diverse collection of cars, trucks, and motorcycles, including a 1996 Ford Mustang SVT Mystic Cobra (#683) and a classic air-cooled Porsche 911.
In addition to writing about cars and wrenching on them in his spare time, he enjoys playing music (drums and ukulele), building model cars, and tending to his chickens.
You can follow Cam, his cars, his bikes, and his chickens at @camvanderhorst on Instagram.

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