COMPOUND TURBO CUMMINS RAT ROD
TYLER SPARKMAN’S CUMMINS POWERED 1931MODEL-A
Rat Rod culture is notorious for scavenging and cobbling together a mix of parts from various vehicles as well as many custom fabricated pieces to craft a unique, one-off machine. So when dairy farmer Tyler Sparkman out of Sparta, Tennessee traded for a 1931 Ford Model-a, he set out for his first custom build to be a legendary Rat Rod. But when he dug in and realized the 350 gasser was in dire straits, Sparkman considered selling the project. That’s when Nick, Sparkman’s brother, stepped in with a paradigm shifting idea and convinced Sparkman to keep the dream alive with a Cummins diesel swap. With the new goal in mind, the brothers set out to transform the quote “unsafe” rust-bucket into a diesel show car in their shop on Sparkman Farm.
Before Sparkman could begin swapping in the new powerplant, he had to address the crumbling frame. He turned to Duck Mcdonald for the fabrication of a custom Z-frame to support the heavier engine as well as strengthen the entire structure. Then he swapped in a 10-bolt axle from a 1978 Camaro and fabricated custom trailing arms and suspended it with Napa shocks and Airride springs for an adjustable ride height and smooth ride when cruising. Up front he kept the ’31 straight axle and transverse leaf spring suspension. To get his lowered machine stopping on a dime, Speedway Motorsports custom rotor and caliper kits were installed all the way around. Dialing in that classic look are 20-inch steel rear wheels with an antiqued green finish wrapped in 255/45R20 Atturo tires paired with 16-inch antiqued green steel wheels up front with whitewall Coker Classic 29x6.00x16 tires.
With the chassis dialed in, it was time for Sparkman to address the body. It takes a lot more work than you might think to craft that Mad Max patina. The Sparkman brothers tackled this job themselves, chopping the top of the cab 4-inches, replacing the floor with custom made pieces, and fabricating a roll cage to be painted the electrifying green accent color. Careful sanding, grinding, clear coat and striping brought out the stunning character the Model-a had earned itself over the years, as well as hitting the mark for the Rat Rod styling Sparkman was after. Just like any true Rat Rod, custom touches like the green silhouetted Cummins logo on the grille, a custom warped wrench hood ornament, a roll away leather top and cleverly relocated taillights are crafted into every nook and cranny of the build. Even the headlight mounts are fabricated from rusty old wrenches that were cut and welded into position to hold the bullet-style headlight housings.
Now Sparkman was ready to give attention to the transplant. A 1997 Cummins 12-valve 5.9L engine was chosen for the swap. The motor was built with ARP head studs, while the injection pump was modified with 191 delivery valves, 4k gov. springs, AFC adjusted for max flow and custom
timing. It was then outfitted with a custom intake horn that is fed the intake charge from the air-toair intercooler installed in the grille shell. Further enhancements to the fuel system include 7x12 DAP injectors and an Airdog II 165 fuel system to deliver fuel up to the modified injection pump. Sparkman also installed a 15 gallon fuel cell in the back of his Rat Rod. To get the power spooling, a BD Diesel compound turbo kit was installed. The ’97 47RH transmission was upgraded with a B&M shifter and a custom Dodge driveshaft was retrofitted. A Derale electric fan trans cooler was also installed in the driver side rear window opening for plenty of airflow. Breathing life into the former rust bucket, this Cummins transplant gives plenty enough power to roast the tires at will.
His dream of a stout Rat Rod was starting to come true, but Sparkman still had to address the interior. K&D Upholstery also in Sparta, TN made some black leather with green stitched seats that well compliment the old school vibe of the simplistic cockpit. Sparkman put together a center con-
sole gauge cluster full of Autometer gauges in the blacked out interior. A quick-disconnect Speedway steering wheel was installed for the classic racer look as well as convenience to slide into the lowered machine. Another of the many subtle custom touches is the custom bent pedals made from old wrenches.
With support from Airdog, DAP (Diesel Auto Power), K&D upholstery and airslamit.com, Sparkman and his brother were able to craft a head turning Rat Rod in their year-in-a-half build. Thinking outside the box is a staple of the Rat Rod community, and this diesel conversion is no exception. From the thought of a Cummins to bending up some box wrenches for reoccurring accents, this Model-a shows the customizer’s creativity and ingenuity from start to finish. Earning many first place Best In Show awards, this ’31 is an absolute show stopper. UDBG
Tyler Sparkman’s jaw-dropping diesel powered 1931 Ford Rat Rod is full of character that keeps heads turning.
With a four-inch chop, clear coated patina and bright green accents throughout, this low riding road warrior doesn’t stop begging for attention. Of course having a monster sized Cummins up front and a compound turbo setup that almost reaches over the roof doesn’t hurt either.
Disc brakes from Speedway Motorsports’ custom rotor and caliper kits all the way around bring the Model-a into the 21st Century and greatly improve drivability and performance. Also notice the cool wrench headlight mount.
The classic ’31 straight axle and transverse leaf spring suspension up front maintain the old school look of the Rat Rod.
Napa shocks and Airride suspension are paired with this ’78 Camaro rear axle to put the Cummins power to the ground and give a good ride; and of course there’s room for some air horns.
The custom green patina paint on the simple steel wheels (20’s in back and 16’s up front) pairs well with the low profiles in the rear and white walls up front.
A Cummins C and bent wrench hood ornament make sure you know this is a custom build with flares of custom fabrication.
This custom feature of a leather roll back roof exposing charred wood supports gives a clever nod to old school styling while adding another unique layer to the build.
Streamlining the taillights up into the body next to the tightened up expanded metal rear window changes the dynamic in the rear to compliment the performance minded Rat Rod’s new style.
All angles are covered as you walk around this unique Model-a. Every time you circle, you’ll find a new detail.
The BD compound turbo kit builds plenty of boost for the lightweight Ford and its exposed plumbing adds to the industrial Rat Rod look.
Another unique touch is this mounting position for the transmission cooler with welded chains as the brackets; it is sure to get plenty of cooling airflow through the windowless opening.
This Cummins swap looks at home with its green accented rocker covers on the 12-valve head and custom plumbing.
Sparkman opted for a 15 gallon fuel cell in the back of his Model-a behind the air tank and alongside the compressor.
With black smoke billowing and white smoke rolling, this Cummins powered Rat Rod proves it mettle.
With a year-in-a-half of work, Sparkman crafted his dream of an all-out Rat Rod with plenty of power and day to day reliability.
Sparkman worked his custom magic again with bent wrenches working as the pedals for his machine.
A quick-disconnect race wheel from Speedway Motorsports and custom gauge cluster full of Autometer Gauges show this Rat Rod is ready for more than looking pretty. Notice the wrench used to loosen the column mount to swing away the shaft to make it easier to get in and out of the low-slung ride.
K&D Upholstery came through with these classic looking black leather seats with green accent stitching.