June 22, 2022

Shawn Fink’s Hemi Twin-Turbo 526 cid engine

The engine of the week is presented by

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

Shawn, who owns Motorsport prodigy in Casper, WY, gave us time to chat on day three of the drag-and-drive event in Gainesville, Florida, where Sick Week competitors were laying rubber at Gainesville Raceway – 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 enginesand it was actually one of Jeg Coughlin’s old Pro Mod motors.

“This engine originally belonged to Jeg Coughlin in 2005,” says Fink. “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, 4,600″ bore and 3,900″ stroke, making it a very stiff engine. Internally, the Hemi construction features a billet crank, push rods forged aluminum and BME pistons.It has an LSM camshaft, which has .790 lift and low spring pressure – .330 in the seat and .850 open.

“Our engine is not the cylinder head version,” Fink said. “It’s still a cast-head Sonny’s, so it’s older stuff, but it works. We had a lot of valvetrain tweaks before we came in and did this. In fact, we worked a few months to change the geometry and square it and grease it under pressure and stuff like that Sonny’s uses specific rocker arms for their engines, and they’re not pressure oiled, which isn’t great for endurance racing , so we went through and pressure oiled the journals and got rid of all the needle bearings and 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 had any issues with the car or the engine.

“So far so good,” he said. “The road trips were great. It works really cool. It’s comfortable. It’s good to be back in the seat.

Part of the engine’s reliability is due to a Peterson R4 five-stage dry sump system that helps keep components lubricated, along with a BigStuff3 Gen4 engine management system, Bubba Ginn Turbo 400 trans and chassis Greg Orr who all contribute to the cause. The Hemi’s power output is aided by two 94mm Gen1 turbos, which Fink says are almost a decade old.

“These have proven themselves,” he says. “We could probably gain a bit if we were to upgrade the turbos, but we’re not even in the power of that stuff so they work.

“This car is also quite heavy for what it is. When we put it together, we wanted it to have all the amenities. It has power windows and a steel roof and quarters – it’s a car. We’re running solid times so far and we’re not even leaning on it. We leave with 6 books. of boost to about 4000 rpm, then increasing it to 30 lbs. It’s still really lazy. The converter is really loose. It only drops 50 rpm on the shift, but it’s still coupled, and you can tell by the mph. He still did over 200 mph. We hope to see times 6 seconds lower at mid-220 mph.

Shawn’s Hemi was developing about 2,500 to 2,800 horsepower during the sick week. However, he said it is very capable of nearly 4,000 horsepower with more boost and a slightly different setting. One thing Fink was sure to point out is that he didn’t pull off this build on his own. He asked a number of people to play a part in getting the car ready for competition, and he was sure to thank them.

“Vince Fankhauser of Wyoming Performance did all the machine work,” he says. “We assembled the engine and it was all sorted from there. Bubba Ginn did the Turbo 400 transmission there. He is out of Cheyenne, WY. I have to thank Ben Davidow and Brian Metz enormously with Performance of Metz in Wisconsin. Greg Orr built the chassis. Everything just came together.

“I couldn’t 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 your eyes to water to see him actually able to do it all. that. He knows 90% of the car. It’s just me and him doing this thing, so I’m blessed. He’s a great boy.”

Shawn and Tyler completed two more rides and two more leads after talking to them in Gainesville. At the end of the sick week, Shawn and his 1955 Chevy managed a [email protected] average mph, which was enough for Shawn to win the Unlimited Iron class.