Video: Watch EFI-U’s 381-Cube 9,000-RPM LSX Mow Through The Gears

[fbvideo link="//www.facebook.com/EFI101/videos/195197908071350/" width="400" height="300" onlyvideo="0"]

Lately, whenever we mention EFI University and LS engines, we’re usually referring to the awesome 11,000-rpm Spinal Tap project which is nearing completion and will soon see duty in EFI U’s Competition Engine Development class. It will mark the third iteration of the CED engine, each one building on the lessons learned and developments made on the previous generation.

However, the outgoing CED engines aren’t just relegated to a corner of the shop to gather dust. As this video shows, what was once a teaching tool, is still teaching, just a different lesson. “That one only goes to 8,500 rpm,” Strader laughed, as we asked him about the video. “That’s actually the old, old one; the original CED engine. The current CED engine is spinning 9,500-9,700 rpm. And then Spinal Tap will give us plenty of room to expand on that number further.”

This particular powerplant, referred to as the “Orange Engine” is quite impressive in its parts list, as some key components still carry a GM part number. “It’s an LSX block which has been bored out to a 4.250-inch bore, which is giant for an LS with 4.40-inch bore centers,” Strader explains. “It’s got a short 3.36-inch stroke – so it’ll spin – for 381 cubic-inches.”

With all that RPM, you might be thinking that there are some intense LS7-style heads atop the shortblock – but you’d be wrong. “It’s got a factory General Motors 243 casting cylinder head on top,” Strader reveals. “They’ve been ported by Tony Bischoff at BES, so they flow.”

One of the really interesting parts of Strader’s CED engines is that they all use throttle body fuel injection systems. The “dual-quad” setup he’s currently running on the Orange engine in the car was discovered and refined in the second-generation CED engine almost a year ago.

And flow they do. On the engine dyno, after its final CED course, the engine made 778 horsepower. From there, a more modern 358-cube took its place in the classroom. However, this engine wasn’t done teaching lessons. “We put [the 381-cube LSX] in the car with a Powerglide and a loose converter, and the combo has been 8.94 in Las Vegas,” says Strader of the notoriously slower track. “In the car, the combination made 595 horsepower to the hubs.”

However, Strader wasn’t happy with such a large power loss and decided to switch to a Liberty clutchless 5-speed and re-dyno the combination. “The thing picked up 112 horsepower – now it makes 707 at the hubs through the Liberty,” revealed Strader. “Besides gaining the adjustability offered by a clutch, that’s a lot of power. I can’t wait to go play with the car – I’m probably going to need a new cage now.”

It’s pretty impressive to see that not only will the precursor to the mind-bending Spinal Tap project live on in a car, but that it will continue to educate as well. “Once the engine was done with its CED life, we took it and raced it in the real world. I think the CED students enjoy seeing the engine they worked on actually out in the real world, not just on a dyno,” Strader says.

“Then, hopefully this year, the car and engine will be used for an on-track data acquisition class, where we’ll be teaching track tuning and car setup. Everything comes full circle for the engine.”

While Strader readily admits that technologically, this is a little-brother to both the current 358 cubic-inch CED engine (which we’ve covered before) and the penultimate N/A LS engine, Spinal Tap, it is still impressive to listen to an 8,500-plus-rpm (closer to an even nine-grand through the traps) LS engine go through the gears, and see that it still has plenty of educational life left in its heart.

Another view of the EFI University Mustang as it’s put through a drag simulation on one of our ProHub 2000 dynos.#LibertyGearbox#LS#RepeatableReliableMainline

Posted by Mainline DynoLog Dynamometers on Wednesday, November 14, 2018

As you can see, while the engine may be the “baby” of the CED engine family, power and RPM-wise, it is still a beast. 

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About the author

Greg Acosta

Greg has spent over a decade in automotive publishing as Senior Editor of Race Pages magazine. In his free time, he is a firearms instructor and volunteer in the police armory.
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