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Prototype LS V10 Engine Discovered And It’s Being Rebuilt

There has long been rumors, whispers and murmurings of General Motors’ work on a prototype LS V10 engine. Guess what? It looks as if the rumors were true, because KC Maxx Performance and VC Fabrication in Kansas City, Kansas, has gotten their hands on it.

Engine Labs reported on the entirety of the find, but this does indeed to have been a prototype V10 engine, sanctioned by General Motors. The performance shop, which specializes in small-block engines, pegged it to be about 10 years old when looking at the technology.

“We had heard of this engine from the source we acquired it from, when I saw it, I knew we had to get our hands on it. Eventually it became available and we acquired it from the supplier who purchased it from GM,” said Lee Masters of KC Maxx.

GM was rumored to be working on a V10 program to replace the 454 big-block for its trucks in the 1990s. However, the program was said to have never gotten past modeling stages.

The V10 engine displaces 455 cubic-inches, or 7.5-liters, and shares more than a few pieces of modern LS engine technology. The block utilizes a 4.00-inch bore, which is shared with the LS2, LQ4, LQ9, LY6, L76 and 4.00-inch stroke found in the LS7, the pistons have reliefs cut in them very much like the OEM design of the LS and the crankshaft uses the LSA/CTS-V 8-bolt flex-plate.

Even more curious is the engine’s ability to utilize GM’s displacement on demand technology, and the D-shaped head port configuration is identical to the LS7. The cylinder gaskets are even stamped with 7.5 and 7.7 branding, which leads one to believe there could have been an even larger displacement V10 in this family.

Now, KC Maxx plans on bringing the engine to life, since the powertrain was acquired in poor condition. The shop purchased the engine as “scrap” with various other pieces along with it. Currently, KC Maxx is designing a custom camshaft for the engine and will build the powertrain to what it feels could have been a factory match.

How much power should it push? It’s potent.

“Our GM sources says that around the time of this engine’s development, GM was looking to get into the V10 market to compete with the Ford pickup V10 and even the Dodge SRT-10 pickup. This engine we are told made 616 horsepower and 789 lb-ft of torque,” Masters stated.

What a brave new world it could have been.

Former GM Authority staff writer.

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