This 6-71 Blown 300C isn't your Typical Hemi

April 20, 2017 / by Bradley Iger

 After the stock engine failed, Matt Leischer decided to build a 6.5-liter Hemi equipped with a 6-71 supercharger!

“It’s like getting all the attention of driving a Ferrari, but without all the resentment!” says ”Mad” Matt Leischer of Laveen, Arizona. His 2006 Chrysler 300C SRT8 isn’t your typical high-buck show car though. Pushing nearly 200,000 miles on the odometer, Leischer’s blown 6.5-liter Hemi-powered post-apocalyptic sedan doesn’t follow the usual hot rodding conventions, and it’s precisely that “what if” approach to what is possible that brought Leischer’s project to life. 

Leischer originally photoshopped an old school blower and bird catcher setup on a Chrysler promotional photo as a joke, but soon decided this wild idea needed to become a reality.

“I had been playing with this car here and there as my daily driver,” he recalled. “A number of years ago, I photoshopped a blower onto a Chrysler promo picture as a goof and hung it up behind me at work. The more I thought about it, the more I started thinking I could actually pull it off.  I'm very much a motor-head, having grown up around the muscle car thing, and modern technology always inspired me about what was possible. I'd never built anything with an old school roots blower – most people said it couldn't be done and make it a daily driver. So? Challenge accepted!”

Old age would eventually take its toll on the original internals of the Hemi, resulting in an intake valve dropping into the cylinder at wide open throttle. The failure provided Leischer with an excuse to rebuild the motor as a “better, faster and stronger” mill.

Homegrown fabrication and problem solving were the heart of Leischer’s project.  “This car isn't so much a project to be completed as it is a test mule for realizing my ideas and experimentation,” he says. The project began in earnest when his wife asked what he wanted for his birthday. “I gave her a one-word response: Blower.”

Leischer fired up eBay and sourced a rebuilt 6-71 GMC supercharger from a T-bucket with a 327 small block Chevy, but he knew going in that finding the supercharger that would give his project the look he wanted was the easy part. “The supercharger setup was built from scratch,” Leischer explains. “Since no kit exists for the blower drive system, I just made my own.  The limited engine bay space made this a challenge, but not impossible. I set a goal to work within the stock engine bay and not modify the radiator support. Also, this was going to pass Arizona emissions and be fully street worthy.”

After some eBay hunting, Leischer sourced a rebuilt 6-71 GMC blower that had previously found use on a 327-powered T-bucket. Finding the supercharger was the easy part though – making it work within the confines of the 300C engine bay would be the real challenge.

While the 6.1-liter Gen III Hemi remained largely stock for the first few years after figuring out how to make 6-71 work with the packaging and mechanical constraints he faced (which involved mounting the blower pulley backward and relocating the radiator forward with spacers), old age finally took its toll on the Hemi, and the #1 intake valve dropped into the cylinder at wide open throttle. “And that, as they say, was that,” he recalls.

The New Mill

Fortunately the failure provided a valid excuse for Leischer to rebuild the Hemi with more potent internals. It’s now a 6.5-liter, 398ci mill by way of a K1 3.975 stroke crank with Molnar forged H-beam rods, custom Wiseco pistons (9.5:1 compression made to use .866" wrist pin for thicker crown), an ATI Super Damper (13% underdrive), a Bullet camshaft (608"/608" lift, 248°/252°@.050, 114°), and 6.1-liter cylinder heads with “hogged-out and shiny’d up ports” that were done by hand by Leischer over the course of more than 40 hours.  

Making the blower work with the Hemi and within the confines of the 300C’s engine bay took some ingenuity that included mounting the blower pulley backward, relocating the radiator forward with spacers, and using a Gen III Hemi damper from ATI that was built with a standard three-bolt Chevy pattern so it would work with the big-block Chevy blower pulley.

He also explained that choosing Wiseco for his custom pistons proved fortunate from more than just a performance standpoint. “The pistons that Wiseco provided turned out amazingly well. I worked with Jeff Clarkin to choose the specs and he had a ton of enthusiasm for my project. That is very important to me since I usually have off the wall ideas, and if the person you're talking to isn't interested, then it kind of takes the wind out of your sails.”

Clarkin spec'd out a set of Wiseco 2816 forgings with some custom touches to take advantage of the newer Hemi head design and provide as much strength as possible for Leischer’s boosted Chrysler. “We even decided on a smaller than normal wrist pin to increase the piston thickness on top,” says Leischer. “This is a problem area of the OEM Mopar design.”

As for the future, Leischer plans to continue dialing in the Hemi’s tune and then hit the track, “where I can start poopin’ parts out,” he quips. For now though he’s content to simply roll around in a rad supercharged Mopar. “Every outing with this car turns into a cool story." 

The Chrysler’s sinister look comes courtesy of a homebrewed concoction of clear plastic dip mixed with black iron-oxide pigment, which was applied with a Wagner Power Sprayer.

Topics: FEATURES, featured, CAR FEATURES

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Written by Bradley Iger