A clean engine bay is easy to draw and hard to build. The real job is packaging everything the truck needs to run: tire clearance, steering shaft path, firewall depth, brake master cylinders, intake ducting, radiator flow, A/C, and charge-air cooling. On LokJaw, that means building around a large supercharged diesel package and an Allison, not pretending those parts are smaller than they are. The front half of the truck is being laid out around function first. We need room for front tubs, cold-air filters, large intake tubes, and three heat exchangers in the nose while still keeping airflow where it belongs. That is why the discussion centers on duct paths, filter size, tube shape, firewall relief, and how to use the available space behind the grille instead of just smoothing panels for looks. The same logic carries through the rest of the truck. Rear tire clearance drives tub height. The transmission and driveshaft package drive tunnel shape. The clamshell bed needs internal structure, latch strategy, and access panels so it stays stiff, opens cleanly, and still hides the hardware. This is what separates a showpiece from a truck that can actually be assembled, serviced, and driven.
The episode opens with a visit to Empire Metal and an introduction to Sean and Erik, whose shop is known for complex custom sheet-metal work. To establish their capabilities, they walk through several notable builds. One is Maximus, the bare-metal Dodge Charger featured briefly in Fast 7 during the final Malibu canyon scene. That car was later clear-coated, but in its bare-metal form it showcased extensive fabrication, including a fully custom engine bay and a bead-rolled firewall. The firewall was made shallower, while the surrounding engine-bay panels were given deeper, more sculpted forms. Louvers and mesh behind the downpipe were added to help extract heat.
They also describe the body modifications on Maximus in detail. The rear widebody was widened 3 inches per side, for a total of 6 inches across the back of the car. Rather than beginning abruptly at the quarter-panel, the widening started at the front of the door, grew to about 1 inch wider by the rear of the door, and reached the full 3 inches by the front of the wheel opening, continuing at that width to the rear. The bumpers were extended accordingly, while the trunk remained the same size and the taillights were moved outward.
Other examples reinforce the shop's range. Sean had worked on Freiburger's F-Bomb during time spent at Wargasser Speed Shop and later again at Nelson Racing Engines, including updates for SEMA 2017. Another project was Troy's personal Mustang, built for Hollywood Hot Rods. That car began life as a convertible Mustang with only 6 miles on it before the rear section from the taillights back was cut off. The rear was narrowed by 8 inches without changing wheelbase, the taillight angle was revised, and the bumper area was reshaped in metal. The shop also fabricated a full diffuser, front diffuser, side rockers, and a one-piece lift-off aluminum roof after removing the vinyl top.
A final example is the 1936 Packard known as the Mulholland Speedster, built at Hollywood Hot Rods. Sean describes it as roughly 90 percent new metal. The hood was original but shortened by 6 inches, with doors added to the hood sides and the louvers removed. The grille was shortened 3 inches and narrowed 6 inches. The fenders and rockers were largely scratch-built, the rear body lifted open, and the aluminum top rotated into the back of the car. Even the details were period-conscious, including umbrellas in the doors and a flask under the passenger seat.
After reviewing past work, the discussion turns to the current truck project and its sheet-metal challenges. The central feature is a clamshell bed with integrated wheel tubs and a wood bed floor. The top bed surface will carry the wood kit, while the lower clamshell section will be paneled in metal. The goal is to preserve the visual character of a wood-bed truck while preventing the underside and mounting hardware from being exposed when the bed is opened.
The team immediately identifies structural concerns. Because the actuators shown in the renderings are positioned relatively far rearward, the bed could deflect significantly when lifted. To reduce that deflection, the actuators should be moved as close to the wheel area as possible to improve leverage. Internal structure will be required between the clamshell skin and the bed frame, likely using vertical sheet-metal sections with flanges at the top to support the wood floor. Removable lower-side access panels are also proposed so the wood bed can be bolted down while keeping the hardware hidden. Those panels would allow access during assembly and service without exposing the underside fasteners in the finished truck.
The next step is to verify tire and tub clearance. The truck is being evaluated with a Nitto drag radial used as a reference tire. Its measured overall height is described as a strong 31.5 inches, and the team checks the truck's available height at roughly 32.5 inches. That leaves about 1 inch of clearance to the bed structure. Because the chassis is designed to lay the pinch, this is effectively the worst-case vertical relationship between tire and frame. Even at full compression, the tire would not contact the tub if the tub is placed at the bottom of the bed lip, and when the truck is actually driving the tire will never sit that high relative to the frame.
Width is then checked using a much larger mock-up tire than the final combination. Joshua's CAD and physical positioning use a 355/25R24 rear tire with a 14-inch section width, mounted on a 24x13 wheel. Even with that oversized package floated as far outward as practical, there is still some room to the outer sheet metal, and no major interference appears with the shock or suspension brackets. Based on a 55-inch total track width including brakes, that mock-up corresponds to roughly a 5.5-inch rear backspace. Since the intended final tire package will be about 2 inches narrower, the team concludes there is adequate room. They estimate about 14 inches of total packaging width in CAD, and note that flange design on the clamshell opening will matter: a half-inch to five-eighths-inch flange with an added quarter-inch return would significantly increase stiffness while preserving clearance and reducing the risk of cracking.
Attention then shifts forward to the transmission tunnel, firewall, and engine bay. CAD shows the engine and plumbing crowding the firewall area, with the firewall landing roughly at the bellhousing. The team expects to push the firewall rearward by 2 to 3 inches for clearance. Engine movement should be minimal because the motor mounts use a through-bolt with an elastomer bushing, limiting motion to roughly 1/8 inch. The larger concern is body movement from old, potentially weak cab mounts, so those mounts may need to be rebuilt or reinforced before final sheet-metal work begins.
The truck will use a Vintage Air system, and the firewall can be skinned on the engine side. The existing firewall already appears to have been modified for a previous GM installation, but the new engine package is much taller. With the intercooler, blower, and liquid-coupled supercharger system stacked on top, the engine is expected to rise another 10 to 12 inches above its current position, making a hood opening almost unavoidable. The intake opening itself is less critical to firewall clearance than the need to maintain good airflow into the back of the supercharger.
The front wheelhouses should be tubbed as well, both for drivability and to visually frame the engine better. The truck will use Wilwood brakes with a firewall-mounted master cylinder and no booster, so the firewall needs enough structure to support the pedal and master-cylinder loads. Air-conditioning lines will pass through the firewall on the passenger side and could potentially be hidden inside the tubs before routing to the compressor. The original steering-column shift linkage will not be retained; the truck will likely use a floor shifter, which affects transmission-tunnel clearance. Wipers are being deleted, which simplifies the cowl area. Cooling requirements are substantial, with three heat exchangers planned: one for air conditioning, one for the supercharger charge-cooler water circuit, and one for the engine coolant. The engine's oil cooler is already integrated, and the batteries will be relocated to the rear.
A major design discussion centers on cold-air routing for the supercharger. The plan is to bring cold air through the nose and into air boxes located low in the front fenderwell area, then route ducts back to the rear inlet of the blower. The preferred filters are Banks' large circular units, referred to in the conversation as the "big ass filters," one on each side. A round air box is favored over a square one for appearance and packaging.
The blower inlet requires a 6-inch inside diameter at the rear, so the ducting needs to preserve as much cross-sectional area as possible. The team considers starting with 6-inch tubing at the filter, then transitioning to an oval section to gain tire and chassis clearance. Sean notes that he has Pullmax dies capable of ovalizing tubing cleanly, and the group discusses not only flattening the tube but also twisting the oval section to snake through the available space. That would allow the duct to pass around obstacles while maintaining flow area better than a smaller round tube. Gale suggests that if the duct must reduce, it should not go below 5 inches, and the CAD currently models the upper section at 4 inches with the possibility of increasing it to 5.
The front sheet metal will be cut and reworked so the tubs can extend downward, creating pockets for the filters. Air entering through the grille area will be ducted so that one portion feeds the radiator and condenser while separate passages feed the intake filters on each side. The idea is to preserve the factory grille appearance while building hidden ducting behind it. The filter housings will be enclosed to keep out water while still supplying cold, low-restriction air. Because the intake tubes will be highly visible whenever the hood is open, the clamps and transitions must also look finished. Conventional clamps may be used at the larger tube connections, while service joints should remain in round sections where possible.
Packaging around the steering and exhaust adds another layer of complexity. The steering shaft must pass from the steering box area to the firewall, likely requiring at least one U-joint. The intake tube location on the driver's side interacts directly with that path, so moving the intake duct forward on one side means the opposite side may need to mirror it for symmetry. The intake manifold itself is a custom arrangement in which boost air enters from below in the valley, passes through the charge-air cooler, then turns 180 degrees into the runners. The upper casting shown is based on an existing marine version developed for an LML application, though the yellow lower section will change because these heads do not have individual ports in the same configuration.
Exhaust routing is expected to begin around 2.25 to 2.5 inches per side before stepping up to a 5-inch outlet through the side of the bed, outside the frame rails. Headers remain under consideration, but space claim comes first. Whatever exits the engine bay may require additional firewall notching, especially near the tubs and steering. If headers are used, they could terminate at a V-band near the tub area, with the surrounding sheet metal scalloped to clear them while still venting heat downward.
Behind the engine sits the Allison transmission, which will require a substantial transmission tunnel. The driveshaft decision is still open between a one-piece and a two-piece design. A two-piece shaft with a carrier bearing under the cab would reduce the need for a large cab notch because the rear section would pivot behind the cab. However, given the power level expected from the truck, the team leans toward a one-piece shaft if length and angle remain manageable. Since the stock bench seat would interfere with the tunnel, the interior will instead use two bucket seats and a center console, which can visually absorb the driveline tunnel if needed.
The rear bed structure is then analyzed in detail. The bed will be split around the perimeter and through the tailgate area, but the Chevrolet lettering should not be cut through the middle. Instead, the suggestion is to lower the Chevy logo toward the bottom and redesign the tailgate so the split line remains visually clean. Inside the bed, new tubs can be built up to the bottom of the fender lip, while the inner side panels and bulkhead are redesigned to accommodate the actuator mounts and hinge structure.
A dual-hinge system is preferred over a simple single pivot because the bed halves need to move without crashing into each other or disturbing the body line. The actuators should mount as far forward as practical, near the tubs, to reduce flex. The first fabrication step will likely be splitting the bed, establishing final bed height, and building the internal frame structure. The tubs can then mount on top of that framework, and the side panels can run down to it. The wood bed dimensions must be known early so any bead-rolled metal panels can be proportioned correctly relative to the wood strips.
When the clamshell is open, both the top and bottom halves must look finished. The internal structure may be 3 to 4 inches deep to hide the wood fasteners and provide stiffness, but the visible surfaces should make the bed appear like a clean top and bottom shell rather than a thick sandwich. Removable underside panels secured with button-head fasteners are proposed to conceal the structure while still allowing service access.
For latching, Sean recommends modern latch hardware rather than traditional truck latches. Corvette-style latches are one option, but Mercedes hood latches, likely from an SL550, may be better because their swivel action gives more tolerance as the bed closes and helps guide the striker into place. A cable-operated mechanical backup release could be paired with an electric actuator so the bed can still be opened if the actuator fails.
With the bed open, the underside becomes a display area as much as a functional one. The team wants to hide the outer bed structure and frame edges while potentially showcasing the central hardware, plumbing, and chassis components as visual "jewelry." The fuel system will use an Aeromotive tank, and the air suspension management will be Ridetech. Air tanks may fit inside the frame rails, leaving the center section open around the driveshaft. Hard lines and wiring in that area are considered critical to the final quality of the build.
The charge-air cooler plumbing and reservoir location are still being worked out. One idea is to place the reservoir behind the cab or even integrate the fill point near the stock-style fuel-filler area so both fuel and coolant service points are accessible together. Because the frame crossmembers sit roughly 2.5 to 3 inches off the ground, there is enough room to route hard lines beneath them without excessive risk. For the pump system, Gale favors a compact inline Stewart EMP pump, which has a small footprint and strong flow. He mentions wanting something north of 50 gallons per minute, though 30 would be acceptable and 40 would be very good. Since the truck will see short bursts of heavy load rather than long sustained pulls, the system mainly needs enough capacity to start with a cold-soaked heat exchanger and absorb heat during those brief acceleration events. Gale also suggests using both a supply pump and a return pump, one pushing and one pulling, to improve circulation through the system.
The meeting ends with a practical plan. The truck will be mocked up further according to the agreed packaging direction, with the body installed, master cylinders mounted, and any necessary trimming done conservatively. Before the truck goes to Empire Metal, everything that will live on the engine needs to be installed so the sheet-metal design can be built around the true final package rather than assumptions. Once that is done, the fabrication can proceed with confidence that the firewall, tubs, intake ducting, bed structure, and all supporting systems will work together.