A Rat-Rod ’41 Chevy School Bus with a P-pumped 12-Valve

Between running a construction company, operating a bar, owning a carwash, and managing several rental properties, life can get pretty hectic for central Illinois entrepreneur, Jason Bliesner. Meet his escape vehicle: a chopped and lowered, Cummins-swapped ’41 Chevy school bus. Thanks to Jason’s rat-rod approach to his people-hauler, the bus retains its original look while also packing a well-fueled, 12-valve 5.9L, compound turbos, and a full air-ride suspension. An updated interior also allows him to bring a dozen friends along for the ride on his much-needed weekend excursions. You won’t always find Jason cruising in the fast lane, but let’s just say his magic school bus gets 15-mpg at 80-mph.

Replacing the original, locked up six cylinder his ’41 Chevy school bus came with, Jason Bliesner had plans to install a 5.9L Cummins from the outset of his rat-rod project. After scoring this P-pumped 6BT out of a Ford school bus, it was torn down so that he could prep it for higher horsepower in addition to starting fresh. Quality Engine Machine Shop (of Litchfield, Illinois), Scheid Diesel, and DeClerck Custom Machine all had a hand in the build, with local truck puller, Drew DeClerck, handling its assembly. While piecing things together, upgrades like ARP main and head studs, a Hamilton 188/220 street cam and tappets, fire-rings, and 180-lb valve springs all made the cut.

The Hunt

On a mission to quench his thirst to build a school bus-based rat-rod, Jason and his father found themselves at an auction 700 miles from home, hoping to be the highest bidders on an old Ford bus. However, when the Blue Oval went for $9,000 they set their sights on following a lead on a Chevy. For a cool $2,700, Jason brought the ’41 back home and then took off for Iowa to pick up the 5.9L Cummins he’d purchased for it. He knew right from the start that he wanted to go diesel with the project. “I like anything weird,” he admitted. “I wanted to do a rat-rod project but do it differently.”

Bringing things to life in the compound arrangement is an S363 turbo from BorgWarner. The T3 flanged, wastegated charger mounts to a factory exhaust manifold that’s been flipped, and routes boost through 3-inch diameter intercooler piping Jason fabricated himself. Once through the Treadstone Performance intercooler, boost enters the ported and polished head via a one-off individual runner intake manifold.

Refreshed 6BT

Though he knew the 5.9L Cummins ran when it was pulled out of the Ford school bus it was powering, Jason also knew it was an eBay purchase. Needless to say, instead of stacking horsepower on top of an unknown engine, the 12-valve was torn apart and treated to various upgrades during the rebuild. Most of the machine work was undertaken by nearby Quality Engine Machine Shop, while Scheid Diesel cut the block for fire-rings and Drew DeClerck of DeClerck Custom Machine assembled the refreshed 5.9L. ARP main and head studs, a Hamilton 188/220 hot street cam with tappets, heavy-duty pushrods, and 180-lb valve springs all made the list, along with port and polish work being performed on the head.

Though Jason installed an instrument panel with a plethora of gauges to his left, the cockpit was kept pretty simple. Here you can see the ididit steering column and Auto Meter Pro-Comp series tachometer. The area under the driver seat was used to store the compressors for the air ride system.
While the exterior was left original for the most part, the cabin was updated for driver and passenger comfort. The seats were pulled from an ’85 Chevy school bus and reupholstered by Mac’s Custom Interiors in Decatur, Illinois. Prior to that, Jason sand-blasted the interior, hit it with an epoxy primer, and then shot it in school bus yellow. The floor was treated to Line-X coating.

Benched P7100, 5×13’s, and Compounds

To fuel the beast, Jason turned to the 12-valve experts at Scheid Diesel. The Scheid team in Effingham, Illinois supplied him with a potent P7100 capable of full fueling to 4,500 rpm, custom-bent injection lines to work with his one-off intake manifold, and a set of 5×13 injectors. Bringing plenty of oxygen to the party is a compound turbo arrangement that centers an S472 above the engine and bolts an S363 to the stock, flipped exhaust manifold. Building 60 pounds of boost is a cinch, with compressed air being crammed through a Treadstone Performance intercooler.

Not looking to complicate the transmission side of things, Jason went with a TH400 automatic to harness the Cummins’ power. Steve’s Transmission Service of Springfield, Illinois reinforced the old-school three-speed’s internals, along with adding a non-lockup converter and a manual valve body. Jason uses a TCI shifter to navigate gears and a line-lock for the occasional burnout.
To keep tabs on boost, EGT, transmission temp, water temp, and a host of other parameters, Jason installed 17 Auto Meter gauges in a custom instrument panel. The panel and console were built by friend, Ben Curtin, of Curtin’s Creations – Welding and CNC Plasma Cutting, and polished by nearby Wheelhop Polishing and Detailing. The push button switches were sourced from Billet Automotive Buttons

14-Bolt and Air Ride

A four-link system and a 14-bolt GM make up the rear suspension and axle arrangement. In order to get the bus’s ride height dropped down where he wanted it, Jason essentially set the 14-bolt rear-end in place and built the floor around it. For proper clearance, he C-notched the frame and fabricated new fender wells. A 3.21 axle ratio—in conjunction with a built TH400 three-speed automatic—allows the Cummins to hum along at 2,700 rpm while cruising 80-mph down the highway. Up front, the independent suspension was robbed off of an ’85 C30 two-wheel drive donor, though Jason had to modified the control arms to make them work. The bus also rides on air springs, front and rear, with dual compressors mounted beneath the driver seat.

All Aboard

Despite the rise in diesel rat-rod popularity over the years, Jason has built something pretty unique with his ’41 Chevy school bus. Between its chopped and lowered stance, the multi-turbo Cummins seemingly spilling out of the engine bay, or its ability to light up the rear tires on command, it draws a crowd wherever Jason takes it. And trust us, his bus makes the rounds. Within the first five weeks of being finished, Jason racked up more than 2,000 miles in weekend trips alone. “It’s a toy,” he told us. “If it’s nice out, I’ll drive it. If it’s not nice out, I’ll leave it in the shed.” Simple as that.

As a Harley rider, classic car collector, and long-time hot-rodder, Jason usually points his creation toward gear head gatherings, so don’t be surprised if his short bus rattles past you at the car show, bike rally, or truck pull. And definitely don’t be surprised if you find it entered in the burnout competition…

After chopping eight inches off of the roof and adding air-ride, Jason’s school bus lost more than a foot of its original height when completely lowered. Believe it or not, he bought the Chevy for $2,700 after plans to buy a Ford bus fell through. When he made the purchase five years ago, the bus was serving as a live-in camper in western Kansas.
In order to stand up to the weight of the B-series Cummins, Jason robbed the front suspension off of a two-wheel drive donor ’85 Chevy C30. The control arms were modified to make the ball joints work, and air bags from Air Ride Technologies were added. Out back, a four-link suspension is employed, along with an air bag on either end of the 14-bolt axle. The 14-bolt, also stolen from the ’85 C30 donor, makes use of 3.21 axle gearing and a Detroit locker.

1941 Chevrolet School Bus


Owner: Jason Bliesner

Hometown: Stonington, Illinois

Engine: 5.9L Cummins with ARP main studs, fire-ringed block, ported and polished head, 180-lb valve springs, heavy-duty pushrods, ARP head studs, Hamilton 188/220 hot street cam and tappets, C-Line/562 Fabrication low-profile oil pan, Canton Racing Products overflow reservoir, Wizard Cooling radiator

Fuel: Scheid Diesel P7100, custom-bent stainless injection lines, and 5×13 injectors, homemade fuel system with FASS 260-gph lift pump, Summit Racing 20-gallon aluminum fuel cell

Air: Custom compound turbo arrangement with BorgWarner S472 atmosphere charger and S363 high-pressure turbo, Treadstone Performance intercooler

Exhaust: Flipped factory exhaust manifold, 5-inch turbo-up system with rain cap

Electronics: Fabricated-aluminum gauge panel with Auto Meter gauges for boost, EGT, transmission temp, water temp, oil pressure, fuel supply pressure, fuel level, air pressure, mph, and engine speed, Billet Automotive Buttons push button switches

Transmission: Turbo 400 three-speed automatic built by Steve’s Transmission with manual valve body, line-lock, non-lockup converter, and TCI shifter

Horsepower: 650 hp (est.)

Torque: 1,200 lb-ft (est.)

Suspension: ‘85 Chevy C30 front IFS with modified upper and lower control arms, rear four-link, Air Ride Technologies air-ride (front and rear)

Rear Axle: ‘85 Chevy C30 14-bolt with 3.21 ring and pinion


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