This engine package is about more than bolting a blower onto an L5P. Once you decide to supercharge a Duramax, the real challenge is airflow path, charge-air cooling, crankshaft control, oiling, exhaust heat, and physical fit in the chassis. The intake side starts with a Whipple 3.8L Gen-5 supercharger blowing into a marine-style liquid-coupled charge-air cooler integrated into the manifold. Air is forced down into the lower plenum, through the water-cooled core, then into the runners and heads. That layout keeps the charge-air cooler compact and puts the cooling where the air needs it. At the front of the engine, the Banks Fluidampr handles more than torsional control. It underdrives the stock accessory belt so higher engine speed does not overspeed accessories, and it provides separate drive planes for the blower and the dry-sump pump. For this truck, dry-sump oiling is mandatory because chassis drop leaves no room for a conventional oil pan. On the exhaust side, the new cast L5P manifolds are built from a heat-stable alloy chosen to survive repeated thermal cycling. They also include pressure and temperature ports so we can measure manifold pressure, turbine-inlet drive pressure, and the losses between them. That matters because exhaust volume and pipe sizing are always a tradeoff between response and peak flow. Even the stock oil cooler became a packaging decision, which is why the later 2020-up L5P cooler is part of the plan. The whole combination is aimed at one thing: making a supercharged Duramax package that fits, survives, and gives us a real foundation for future L5P-based performance crate engines.
The episode opens by explaining why Banks is putting an extreme blown Duramax into a weathered 1966 farm truck. Gale says the truck is serving as a development platform for a series of L5P Duramax-based performance crate engines. The broader plan includes multiple configurations: turbocharged versions, supercharged versions, combinations with nitrous, and even compound arrangements such as two turbos with a blower or one turbo with one blower. This particular build is intended to establish the first version, a supercharged package aimed somewhere in the 700 to 800 horsepower range, with the possibility of approaching 1,000 horsepower depending on the final combination and whether nitrous is added. The goal is not to build a conventional restoration, but a street-oriented truck that looks intentionally out of place for the level of power and engineering underneath.
Gale also addresses questions about the scale and style of the project. He notes that Banks does not approach production or engineering halfway, and that the video presentation is produced in-house rather than by an outside television crew. When asked where he has been, he explains that much of his recent time has gone into patents, including a newly awarded patent for the PedalMonster throttle booster and another for a new oil-control system dealing with lube-oil aeration and temperature control in the oil pan. He also mentions work on a new dyno and emissions facility and expansion of the Banks campus. In response to criticism that the truck is being built only for millionaires, Gale frames it as a hobby project that could be done in a home garage over time, even if it takes years rather than months.
The team then answers questions about the chassis and front suspension. Erik explains that they are not using stock GM suspension, so a stock GM 3500 spindle and hub arrangement would not simply bolt into the Roadster Shop setup. Roadster Shop typically uses a Pro spindle in its own suspension systems, but this truck is expected to carry a blown Duramax, large Wilwood brakes, and the loads associated with an eight-lug heavy-duty package. To solve that, they worked with Kibbetech to retain the stock-style hub bearing while designing a custom spindle that fits the fixed ball-joint spread required by the Roadster Shop suspension. That allows the truck to keep the strength and packaging needed for the intended abuse while also accommodating the Wilwood brake package.
Wheel size follows directly from the brake choice. The truck will use 15-inch front brake rotors, which immediately pushes minimum wheel diameter to around 20 inches once caliper and package clearance are considered. With an eight-lug pattern and the overall hot-rodding theme of doing something different rather than following the usual formula, the larger wheel choice is presented as a practical consequence of the brake system as much as a styling decision. One viewer also asked whether the truck could retain its wood bed floor, and the answer is yes. The original wood floor is being kept, with the expectation that its final finish can be made to complement the truck's existing rusted exterior.
With the truck at Roadster Shop for 3D scanning, the immediate engineering problem is packaging. Roadster Shop needs to know exactly what engine and accessory layout it must design around, because frame rails, mounting points, suspension geometry, and control-arm placement all depend on the final engine envelope. Gale describes the challenge as trying to fit 50-caliber ammunition into a 38-caliber revolver: the engine package is large, and the chassis will have to be built around it carefully.
To help define that package, Gale and Joshua from the mechanical engineering group walk through a mockup of the induction system and front drive. The discussion is not about cosmetic appearance yet; it is about establishing the hard points that Roadster Shop must clear. The width of the engine, the location of the exhaust manifolds, the oil cooler, the dry-sump drive, and the transmission pan all matter because this truck is intended to sit very low and even "lay frame." That means the lowest components cannot be vulnerable to hitting the ground, so crank centerline height and underbody packaging become critical from the start.
A major part of the package is Banks' integrated intake manifold and water-cooled charge air cooler, originally developed for marine engines. Gale explains that versions of this manifold have already been sold for pull trucks, where a front-mounted water tank, pump, and low-temperature radiator can circulate coolant through the core, or where ice water can be used for short-duration competition. In marine service, the system has already been tested in boats, including a Navy application with two engines in one boat.
The manifold uses an integrated core placed inside the plenum. Air enters the lower portion of the manifold, passes upward through the charge air cooler core, and then exits into the upper section where the flow is radiused into the runners feeding the cylinder heads. Earlier Duramax engines used eight individual intake ports per head, and Banks had built tuned runners accordingly, effectively applying ram-tube tuning to a diesel. For the L5P, the port arrangement is different, so the runner and plenum geometry will change. Instead of eight separate upper runners in the same form, the final L5P version will likely use four larger passages per side while still feeding the plenum appropriately.
The core itself is cupro-nickel, chosen specifically so salt water can pass through it without destroying the heat exchanger. Gale points out that raw aluminum would survive only a short time in salt-water service. Production marine versions also use zinc anodes as sacrificial material to protect the system. The water end cap includes a divider so coolant enters and exits correctly through the core, and the team notes visible deposits from prior testing on city water. The integrated design allows the induction package to support different boost sources. With turbocharging, a compressor can be aligned to blow into the lower inlet plenum. With supercharging, a mounting plenum sits on top and the blower discharges downward into the manifold, past the water cap area and into the lower plenum before the air rises through the core.
For this truck, the supercharged arrangement is the focus. The blower mounts above the intake manifold, and the mockup shows the general orientation of the inlet and filter arrangement, though Gale makes clear that the final appearance will be much more refined than the rough blocking pieces being used for packaging. What matters now is the blower location, the drive path, and the space required at the front of the engine.
Banks is developing a racing viscous damper for the Duramax, and this component becomes the foundation for multiple belt drives. The damper assembly includes separate belt planes: one for the stock accessory drive, one for the dry-sump system, and one for the blower drive. The stock belt plane has been made smaller because the engine will be turned faster than stock, and Banks does not want to overdrive the accessories at elevated engine rpm. In other words, the accessory system is intentionally underdriven so the engine can safely run higher speed without overspinning driven components.
The dry-sump drive uses a 20 mm belt, while the blower drive uses a 12-rib arrangement. Gale says he wants to move away from the traditional cog-belt style often associated with roots-blown race engines and instead use the 12-rib system because it allows tighter belt wrap if needed. The blower under consideration is a new 3.8-liter Whipple. The target blower speed is in the 18,000 to 20,000 rpm range, and Gale notes that Whipple is working on step-up gears for the front case if additional shaft speed is needed to reach the ideal operating range. So far, the fastest engine speed they have run is 6,300 rpm, which informs the damper tuning and drive ratios.
Gale spends considerable time on the damper because he sees it as a critical reliability component rather than an accessory. The viscous damper is tunable by changing the inertial mass of the internal ring and by changing the viscous fluid to alter shear and damping characteristics. Different ring materials, such as cast iron or bronze, can change density and therefore inertia without changing the damper's external size. That makes the unit adaptable to different engine combinations and rpm ranges.
He contrasts this with dampers that rely on rubber O-rings or elastomer elements that degrade with heat and require rebuilding. In his view, that approach is unacceptable for serious service. The Banks damper is intended to survive 500,000 miles while still being suitable for racing use. He also notes that the assembly includes a six-bolt pattern that can drive additional pulleys if needed. Another important detail is crankshaft timing. On the L5P, stock timing references a trigger wheel at the rear of the crankshaft, which would require cutting part of the counterweight away in some configurations. Gale does not want to do that, so Banks uses an O-ring plug arrangement to blank that area and handle the front-drive strategy differently.
Because the truck is intended to sit extremely low, a dry-sump oiling system is mandatory. Gale says that if the truck lays frame, a conventional oil pan would be crushed, so the stock wet-sump arrangement cannot be used. The dry-sump pump is packaged at the front of the engine and driven from the dedicated belt plane on the damper. This allows the lowest point of the powertrain to move upward, likely making the transmission pan the lowest major component rather than the engine oil pan.
Gale mentions that Banks has not yet tooled the oil pan design that incorporates his newly patented oil-control inventions, and in any case that concept would still be too deep for this truck. The dry-sump system is therefore the practical solution for this chassis. The team also checks the Allison transmission pan depth because crank centerline height relative to the bottom of the pan and the frame rails determines whether the truck can drop to the ground without contacting the street. They identify the shallow Allison pan as the one in use, and note that Roadster Shop will need to account for crossmember placement and overall underbody clearance when finalizing the chassis.
One of the biggest fitment concerns is engine width at the rear, especially near the exhaust manifold flanges and upper control-arm mounts. The team measures the width across the rear flange corners at just under 30 inches, roughly 29 1/8 to 29 3/16 inches. That is tight, but potentially workable within the planned frame-rail spacing. Gale identifies the exhaust manifold flange area as the widest point and expects heat shielding to be necessary because suspension components, bushings, urethane parts, or airbags may end up close to the manifolds.
The exhaust manifolds themselves are made from a high-stability alloy that Gale says Caterpillar developed for severe-duty use. The material resists corrosion, tolerates repeated heat cycles, and remains dimensionally stable without cracking, growing, or shrinking excessively. The downside is that it is difficult to machine, but Gale insists on using it for durability. The new L5P-style manifold castings will likely gain bosses for attaching heat shields. Earlier Banks Duramax manifold kits included a driver-side heat shield mainly to protect steering components in stock pickups, but this truck will require more comprehensive thermal management.
The manifolds also include ports for exhaust pressure and exhaust temperature measurement. Gale wants to know drive pressure directly at the manifold outlet because that is the pressure the piston works against during the exhaust stroke. He also wants pressure measured at the turbine inlet so he can calculate pressure loss through the up-pipes. Minimizing that loss is important, but he cautions against simply making the pipes huge. Larger volume slows response because the exhaust system has more volume to fill before the turbine sees a strong energy pulse. The design therefore has to balance drivability and peak performance. Stock GM sizing is well judged for a pickup at stock power, but this engine will move much more exhaust mass, so Banks will enlarge the system only as much as necessary rather than oversizing it.
Another possible interference point is the stock oil cooler assembly, which could have conflicted with the frame. Gale brings out the later L5P oil cooler and notes that the 2020 or 2021 version is better than the 2017 through 2019 version, which itself improved on earlier designs. He wants to retain this cooler, and when the team checks its width relative to the exhaust manifold envelope, it appears to fit just inside the same roughly 30-inch boundary. That is encouraging because it means the cooler may remain in place without forcing major compromises.
The mockup also highlights an obround section of tubing used for firewall clearance. Gale notes that this kind of flattened tubing is common in NASCAR exhaust systems where ground clearance is limited, and the same idea is being applied here to preserve flow while fitting the available space. By the end of the walkthrough, the team has roughed out the major engine package: integrated water-cooled intake manifold, top-mounted supercharger, multi-plane front drive with racing viscous damper, dry-sump oiling, Allison transmission, stock-style oil cooler, and heat-managed exhaust manifolds. Gale closes by saying that the internal engine details remain a separate piece of the story and will be shared later. For now, this model is what goes to Roadster Shop so the chassis can be designed around the real packaging constraints.