Video: 10,000+ RPM Dart LS Next Pro Stock Engine

We here at EngineLabs like to call 10,000 rpm the magic number. In the case of a racing engine, the five-digit RPM level is a major measuring stick where you can truly see if an engine has been designed for competition purposes; for a racing V8 engine, it’s often the mark that separates the winners from the wannabes. In the case of this insane LS Next-based engine based on a Dart block and cylinder head castings, and Book Racing Enterprises‘ engine building prowess, they’ve not only eclipsed the 10K rpm mark, they’ve done it during the first dyno session on this development engine — and made race-winning power right out of the box.

The engine’s creation came out of one concept: Richard Maskin’s desire to create an LS Next-based engine that could produce gobs of power without costing the end user an arm and a leg to procure. With a stated cubic inch dimension of 400, and a goal of making 3.0 horsepower per cubic inch — specific output figures to rival that of NHRA 500-inch Pro Stock engines, and right on par with small-block 400 ci Aussie Pro Stock engines — the team had no shortage of challenges along the way. Ultimately, as the first LS Next engine of its kind, this became a two-year-long project.

The compacted graphite iron LS Next block uses an 8.880-inch deck height in this all-out naturally-aspirated engine. The traditional LS deck height is 9.240-inch.

“We took the best engine and took it to the best engine builder and let him build it — that was the theory,” says Maskin. “I wanted to prove out certain components were going to be the best LS components. Even though someone might not build an engine quite like mine, the heads on it are unique for an LS.”

Maskin — the owner of Dart — and Bob Book of BRE have been friends and colleagues for a long time, and when Maskin conceived the project and invited Book to lend his talents to the program, Book was thrilled. For the unaware, Book’s engines have been incredibly successful in Australia, where they dominate the small-block Pro Stock class. It was a natural fit for him to work together with Dart on this project, as they share a love for naturally-aspirated engines and the science of building horsepower.

“Richard believed in us enough to have us build the engine and was also incredibly open to listening to the ideas that we had,” says Book.

As with any naturally-aspirated engine, induction is king, and it appears Dart has nailed it with their 10-degree cylinder head. We’ll be covering the development process for these in a future article right here on EngineLabs.

What’s Inside

Currently, there are two stumbling blocks for a racer when it comes to competing with this type of all-out naturally-aspirated engine. First, the cost of entry is astronomical when compared to a power-adder engine which outputs the same amount of power. Secondly, the group of people on the planet who are capable of making 3 horses per cube — and are willing to talk about it, or sell their services — is extremely small, and the chances are if you don’t know the right people, you’re not getting into the club.

Book says this engine, and its readily-available components, will change all of that. There is a part number for the valves at Victory, a part number for the rocker system at Jesel, and there are very few one-off parts. The development has already been done by Maskin and the Dart R&D team to provide components which are already scienced-out from the jump.

Rochard Maskin and Bob Book are two legendary figures in this industry, with decades of championship-winning experience between them. When two experts like this get together the results are bound to be impressive–and they are!

The compacted-graphite iron LS Next block used as the foundation for this engine does not use standard LS deck dimensions of 9.240-inch — instead it uses a shorter 8.880-inch deck height — which puts the engine at the 400 ci limit to keep it legal for the Aussie Pro Stock class and the NMCA’s Pro Stock class, which also uses a 400-inch rule.

“He incorporated some of our ideas into the cylinder head. We’ve been building the 400 ci engines for a while now. He was awesome to work with, and this is going to be a really nice piece. For our first shot at it, we made power that’s 6.90 power in the class [Aussie Pro Stock, which runs at 2,300 pounds]. The head and the block are directly from Dart. They sent them to us and we didn’t do anything to them — we ran them on the engine as sent,” Book says.

The length of the MGP connecting rods is the one engine specification we weren’t able to get Bob Book to divulge.

Dart’s 10-degree LS heads are, in short, a radical departure from anything else offered on the market for this engine platform today. Not only do they have a raised Pro Stock-style oval port, canted valves, and wedge-style chambers, the symmetrical intake and exhaust port locations have been reversed to provide the straightest, most efficient airflow path possible.

“By the time you get a set of Pro Stock heads from one of the top guys you’re at $12- to $14,000. These heads will be half that,” says Book.

“These were designed with the American market in mind. My goal is to see these find a home in the NA classes right away, from Competition Eliminator to True 10.5 and NMCA Pro Stock. There were no corners cut here.”

The head can be used on a much bigger small-block engine as well and will perform suitably in all-out competition applications. Book says a 468 or 480-inch small-block engine with a taller deck and power-adders in front will be no problem at all, since the casting and its performance capabilities are extremely flexible. Maskin says a racer could build a sportsman-style version of this engine and turn it 8,000 to 8,500 rpm and still make use of the cylinder head’s capabilities.

Sky High

Building an engine like this is not without its challenges.

“A lot of this is the first time. The first time with anything is the hardest,” says Maskin.

So how did they achieve the magical 10,000 rpm mark with this engine? They actually turned it to 10,300, and Maskin says the engine is perfectly happy at that number. When the engine was still in the design phase, he reached out to several suppliers for their assistance in creating shelf-stock parts that were the best available for this particular cylinder head platform. For example, a set of Jesel shaft-mount rocker arms were designed for stability; these are driven by a 65mm-core camshaft from Cam Motion. In fact, Book says this is the first camshaft they’ve even tried in the engine, and as the development of the platform continues on the BRE dyno they’ll try other configurations to see how the engine responds.

Valvetrain components from Jesel provide the required stability at the stratospheric RPM levels where this engine lives.

For the type of RPM this specific application sees, the deck height dimension is critical; for connecting rod length and pushrod length and valvetrain geometry and intake manifold sizing. As Maskin put it during our discussion, “It’s all about the column of air.”

There are a few parts here which are not traditional; the Winberg crankshaft uses 302-sized main journals at 2.249-inch instead of the 2.559-inch traditional LS specification. Bore size is 4.200-inch, with a short stroke of 3.600-inch. There is also a small-diameter rod pin on the crankshaft; these component dimensions help to keep weight down and RPM capability up.

The complete engine is, in Maskin’s words, “A continuation of Pro Stock Truck technology.”

In a naturally-aspirated engine the reduced bearing size means there can be more meat in the main journal itself, which can help keep the engine from spitting out the crankshaft at high RPM levels. MGP connecting rods of undisclosed dimensions swing a set of CP pistons wrapped in Total Seal rings. Trend Performance DLC-coated piston pins and pushrods are also used.

A six-stage dry sump system uses a Dailey Engineering pump along with a Stef’s pan and oil tank, while Jesel components are found through the valvetrain in the form of rocker arms, belt drive, and roller lifters.

Of course, there is a pair of BRE-built 2.190-inch x 1.910-inch optimized carburetors atop the HRE fabricated manifold. Performance Welding’s headers are the pieces used for R&D and will be the ones Book will recommend to anyone purchasing this engine package.

“I had a number in mind when we started this that I hoped for based on previous experience, and it made as much as my highest expectation for it right off the bat. We’re really pumped about it, and really privileged that Richard had the confidence in us to take on a project like this,” says Book.

They’re still refining the package and will be incorporating running changes into the package as they develop new features, but its performance is beautifully impressive already, even more so when you realize that they haven’t even spent an entire day with the engine on the dyno yet. The result of their testing so far? 2.9 horsepower per cube — which equates to 1,160 ponies stomping on the dyno needle. We’ll be watching the development of this platform closely!

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About the author

Jason Reiss

Jason draws on over 15 years of experience in the automotive publishing industry, and collaborates with many of the industry's movers and shakers to create compelling technical articles and high-quality race coverage.
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