Holley's Rolling Test Bed '74 Chevelle Wagon Runs in the 10s with a Stock Block and Holley EFI

By: Todd Veney l Images by Wes Duenkel07/11/2018 < Back to Blog Home
Would someone actually attempt to make a stock-block '74 Chevy Chevelle wagon run in the 10s? Tim Grillot and the team from Holley would – they did. Instead of seeing another long-forgotten kid-toting grocery getter from the Gas Crunch era, they envisioned the 4,600-pound behemoth's potential as a platform to showcase Holley's all-new LS turbo manifolds. By the time Grillot and crew were done, the two-ton beast was making more than 900 horsepower at the rear wheels.

A rolling test bed for Holley Performance components and a fun project collaborated on by numerous Holley personnel, it all started when Holley President and CEO Tom Tomlinson found the car, which had just 43,000 miles on it, in Colorado. He challenged Grillot to get the car to run in the 11-second zone at the drag strip. Grillot upped the ante – he got it in the 10s.

"Tom loves this car," said Grillot, an Iowa native who's been at Holley for four years and recently was promoted to Director of Engineering. "This was his vision. You wouldn't think a car like this with just a stock 6-liter could run that quick, but I've been around this LS turbo stuff for a while now, and I know what kind of power they can make. I knew the car could do it – it's math."

The car has been a rolling testbed for components from the Holley family of companies since the initial build was completed seven years ago. The team removed the entire body, lowered the suspension, ditched the gutless small-block the car came with, and stuffed a 6.0L LQ9 truck engine straight out of a boneyard in the cavernous engine compartment. Other than the addition of an aftermarket camshaft from Brian Tooley and PAC valve springs to handle the power produced by the turbocharger, the long block remains virtually unchanged from its stock configuration.

Above the camshaft, it's a whole 'nother story. Long gone are the dual carbs from 2011; the installation of a 76mm turbo is what propelled the latest iteration into the 10-second zone. The lumbering sleeper has a slew of Holley components under the hood, including a Holley Dominator EFI ECU, fuel rails, injectors, pressure regulator, Hooker LS turbo manifolds, Holley accessory-drive kit, brushless VR1 fuel pump , HydraMat fuel-reservoir system, and Earl's plumbing. A Holley EFI digital dash kept Grillot appraised of all the engine's vitals when he took the car to Beech Bend Raceway Park in Holley's hometown of Bowling Green, Ky., to see what it could to on the track.

What it did was exactly what Grillot said it would – it ran a 10.89 at 129.93 mph – despite having virtually no boost off the starting line. Plopped on a bench seat and secured by just a lap belt, he dropped the column shift into Drive, rolled up to the Beech Bend starting line, and let 'er rip. "If the car had a trans-brake, it would have run well into mid-10s for sure, but with no trans-brake, stock drum brakes in the back, and stock disc brakes in the front, it's impossible to build any boost without pushing right through beams," he said, "but it really comes on hard at the finish line."

Everything was accomplished with the stock rear end and gears, a 4L80 trans, power steering, and even air conditioning. "It's not hard to make power with a turbo LS," Grillot said. "It's not uncommon to make more than 1000 horsepower with a stock LS. You can blow up a lot of stuff if you don't have the tuning – especially the timing – spot on, but if it's right, you can really make a lot of power."

Matt Lunsford, who has years of experience with LS turbo setups and an LS turbo-powered eight-second Mustang of his own, did all the tuning, and Holley lab techs Logan Duvall and Lucas Embry handled the mechanical and assembly work. "A lot of work went into this," Grillot said. "Building the turbo headers themselves can be the hardest part of upgrading to a turbocharged setup, but now all that work is done. Now, with almost any chassis, these new Holley LS turbo manifolds and crossover tubes will bolt right on your car."