Classic American Muscle Meets Diesel

By KYLE TOBIN

They told him it couldn’t be done, but Ryan Lusk was destined to build a uniquely American hybrid. No matter what anybody said, Ryan knew a Dodge truck/Chevy Corvette was going to hit the drag strip, and his father and two brothers were backing him up.

INSTIGATOR

It all started when Ryan’s dad, Steven, tossed around the idea of shoving a diesel into an old Corvette. The thought was met with jokes as most thought it couldn’t be done. But after the laughter settled, the idea stuck in Ryan’s head like a tent peg in the dirt: It would be a serious undertaking, but to Ryan, it would be a worthwhile endeavor. A through-and-through diesel technician from a family of gear-heads, Ryan knew that with the help of his kin, they would be able to conjure up the solutions to melding a cumbersome diesel motor into the slick fiberglass sports car.

CUMMINS POWER

With Ryan’s background in hot rod gasser Chevys coupled with over a decade of sled pulling experience, he knew a Cummins would be great in his future drag racer. So, a hearty first gen 12-valve would become the starting point of the build. Strengthening the engine for the abuse of drag racing, Ryan tore down the motor and sent it out to be machined at Petite Machine in Winterset, Iowa. Then, he installed polished and balanced rods swinging a set of 0.030-over Cummins pistons along with a performance cam and Smith Brothers 7/16-inch pushrods with 24v lifters in the block. The ported and polished cylinder head used 160-pound valve springs to tame the valves and keep them under control even with high boost pressure. To keep the engine cool under the high-heat, fast-paced drag runs, he went with an aluminum radiator and a pair of high flow electric fans to fit in the confines of the engine bay.

Not a lot of heavy modifications were needed to bolster the stout motor for the light chassis it was intended for, but Ryan and kin didn’t stop at the long-block. To get the fuel flowing, Ryan opted for a modified P7100 injection pump delivering plenty of fuel to a set of 5 X 0.018 injector nozzles to feed each cylinder with loads of #2. In order to get the desired boost to propel the ‘Vette across the line first, additional aspiration was needed. Ryan fitted the Cummins with GT 4294 over 5364 compound turbos to blast down the track. He plumbed a custom inter-cooler into the front of the Corvette then back to the engine to keep the intake charge cool under pressure. These powerful upgrades combined to offer Ryan an estimated 700 horsepower pushing approximately 1,400 lb./feet of torque. All this caged inside a car weighing roughly 4,000 pounds—including the engine itself—is a stout combo.

Custom motor mounts that Ryan and his family fabricated would allow the engine to slide into the heavily modified engine bay of the American sports car. To get the exhaust gasses out of the engine, he used a custom 5-inch downpipe leading into the passenger side 4-inch Grand Rock Turnout sidepipe that bellows a mean sound and plenty of black smoke under throttle. However, to put the power to the ground would take some doing. Starting with the transmission, Steve Lusk built a 47RH transmission from a ‘95 Dodge truck with a 3,000 RPM stall Diesel Performance Converters billet triple-disk torque convertor with a Pro Street Diesel valve body. Gear selection is actuated by a Hurst pistol-grip shifter mounted above the transmission tunnel. The custom drive shaft links the transmission to the straight axle rear end that replaced the original Corvette IRS axle assembly.

A 4,000 lb. car with 700 horsepower and 1,400 pound feet of torque”

CHASSIS SUPPORT

To hold the track, the chassis would need some tweaking as well. The front of the frame stayed stock, but the rear half was modified by Ryan to accept the beefy Quick Performance 9-inch axle housing stuffed with 3.50 gears and Moser Engineering spool and axles. Lusk upgraded the front suspension to big-block Chevy springs and 4-linked the rear axle with a set of coil over shocks. Centerline Convo Pros were Ryan’s wheel of choice, running 15X6-inch in front and 15X14-inch in the back. Wrapping the Centerlines are Wynstar Phaser R21 195/60R15s in the front and Hoosier Quick Time Pro 31X18.50-15LT DOT drag tires in the rear, ensuring a solid bite on the track round after round. To slow down the ‘Vette at the end of each run, Ryan relies on factory disk brakes up front and big 4-piston calipers in the rear. Switching to a 17-gallon plastic fuel cell and relocating the battery to the rear allowed some flexibility in weight distribution along with complying with race rules.

SWEATING THE SMALL STUFF

With an impressive drivetrain built came the daunting challenges of modifying the ‘68 Corvette to house the Cummins and its accoutrements. Ryan was able to maintain the overall look of a classic ‘Vette set up for drag racing, even augmenting a blower-style scoop to the top of the engine that pops through the cowl induction hood, giving the car a classic, aggressive look. But to keep the stock front clip and bumper, Lusk and his family had to modify and fabricate a custom one piece tilt up front end, adding another unique flare to the racer. Taking one more queue from Dodge to splash a stunning color across the Corvette and grab even more attention, Ryan had the car painted in a special Viper color Metallic Copperhead.

The modifications weren’t over yet as the interior got its time. Ryan swapped in a sweeping ‘63 Corvette dash that houses Isspro Performance gauges down the center to streamline the simple, fabricated look of the cockpit. Throughout the vehicle, an 8-point cage was retrofitted into place to heighten safety as they rocket down the strip. In a similar vein, Ryan installed race seats and mounted 5-point harnesses. The ‘Vette was ready for the track.

“Taking one more queue from Dodge, Ryan had the car painted in a Viper color Metallic Copperhead”

From a tossed around idea and a belief in the impossible, Ryan and his family triumphed over the odds and created a unique, eye-catching drag racer ready to eat up the track. With 700 diesel horses squeezed under the hood of this ‘68 Corvette, Ryan Lusk holds the reigns to a wild beast at the height of custom American motor-sport lore. No one could stop him and his family from creating a one-of-a-kind muscle car that turns heads with its rumbling Cummins’ diesel. And the striking ‘Vette doesn’t fall short on the track either as it hurtles up to 130 MPH for an 11.42 quarter mile pass. This “hybrid” came together combining parts of a Dodge truck with a classic sports car and shows that commitment can help a man produce dreams. UDBG

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