Shawn Fink’s Twin-Turbo 526 cid Hemi Engine - Engine Builder Magazine
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Engine of the Week

Shawn Fink’s Twin-Turbo 526 cid Hemi Engine

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Is it just us, or is there something special about a 1955 Chevy 210 Belair? It’s a gorgeous-looking car, and when you watch one go 200+ mph down the track, you can’t help but love it even more! We got an up-close look at Shawn Fink’s orange 1955 Chevy during Sick Week 2022, and spoke with him about the details of his twin-turbo 526 cubic inch Hemi-style Sonny Leonard engine tucked under the hood.

Shawn, who owns Prodigy Motorsports in Casper, WY, gave us some time to chat on day three of the drag-and-drive event in Gainesville, FL, where the Sick Week competitors were putting the rubber down at Gainesville Raceway – the home of the NHRA Gatornationals. Fittingly, Shawn recorded his best ET of the week there – a [email protected] mph. Shawn told us that the 526 Hemi engine in his car was built by Sonny’s Racing Engines, and it was actually one of Jeg Coughlin’s old Pro Mod engines.

“Originally, this motor was one of Jeg Coughlin’s from 2005,” Fink says. “We chose this block because it is a fully water-jacketed CN block. It runs a conventional, big block Chevrolet water pump, as well as other big block Chevrolet accessories.”

The Hemi-style engine has a 5.000” bore space, a 4.600” bore and a 3.900” stroke, which helps make it a very rigid engine. Internally, the Hemi build features a billet crank, forged aluminum rods and BME pistons. It’s got an LSM camshaft, which has a .790 lift and low spring pressure – .330 on the seat and .850 open.

“Our engine isn’t the billet-headed version,” Fink says. “It’s still a cast-headed Sonny’s, so it’s older stuff, but it’s working. We’ve had a lot of valvetrain adjustments prior to coming and doing this. We actually worked a couple months changing the geometry and getting it squared up and pressure oiling it and stuff like that. Sonny’s utilizes specific rockers for their engines, and they’re not pressure oiled, which for endurance events isn’t great, so we went through and pressure oiled the trunnions and got rid of all the needle bearings. I machined a bunch of bronze bushings for it and pressure oiled it.”

Shawn mentioned that Sick Week was his first event with the car in six or seven years, and they hadn’t run into any problems with the car or engine.

“So far, it’s going good,” he says. “The road drives have been great. It runs really cool. It’s comfortable. It’s good to be back in the seat.”

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Some of the engine’s reliability is thanks to a Peterson R4 five-stage dry sump system helping keep components lubricated, as well as a BigStuff3 Gen4 engine management system, a Bubba Ginn Turbo 400 trans and a Greg Orr chassis all helping the cause. The Hemi’s horsepower output is aided by twin 94mm Gen1 turbos, which Fink told us are nearly a decade old.

“These are tried and true,” he says. “We could probably pick up quite a bit if we were to upgrade turbos, but we’re not even into the power in this thing, so they’re working.

“This car is also pretty heavy for what it is. When we put it together, we wanted it to have all the amenities. It’s got electric windows and a steel roof and quarters – it’s a car. We’re running some solid times so far and we’re not even leaning on it. We’re leaving on 6-lbs. of boost at about 4,000 rpm, and then ramping it up to 30-lbs. It’s still really lazy. The converter is really loose. It’s only dropping 50 rpm on the shift, but it’s still coupling, and you can tell that by the mph. It still did over 200 mph. We hope to see lower 6-second times at mid-220 mph.”

Shawn’s Hemi was cranking out around 2,500-2,800 horsepower during Sick Week. However, he said it’s very capable of close to 4,000 horsepower under more boost and slightly different tuning. One thing Fink was sure to point out was that he didn’t make this build happen on his own. He had a number of folks play a role in getting the car ready to compete, and he was sure to thank them.

“Vince Fankhauser with Wyoming Performance did all the machine work,” he says. “We assembled the engine and got it all squared away from there. Bubba Ginn did the Turbo 400 transmission in it. He’s out of Cheyenne, WY. I have to give a huge shoutout to Ben Davidow and Brian Metz with Metz Performance in Wisconsin. Greg Orr built the chassis. Everything has just come together with it.

“I could not do any of this without the help of my son Tyler. He’s been doing this with me since he was 13 and he’s 23 now. It brings tears your eyes to actually see him be able to do all this. He knows 90% of the car. It’s just me and him doing this stuff, so I’m blessed. He’s a great kid.”

Shawn and Tyler completed two more drives and two more tracks after we spoke to them in Gainesville. By the end of Sick Week, Shawn and his 1955 Chevy managed a [email protected] mph average, which was enough for Shawn to win the Unlimited Iron class.

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Engine of the Week is sponsored by PennGrade Motor OilElring – Das Original, Scat Crankshafts and Engine & Performance Warehouse Inc./NPW Companies. If you have an engine you’d like to highlight in this series, please email Engine Builder Editor Greg Jones at [email protected]

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