A normal dump bed tips the whole box. That would not work here. We split the ’66 Chevy C20 bed horizontally, kept the lower section fixed, and engineered the upper section to scissor open. The hard part is geometry: the upper bed has to lift away first, then rotate back, without crashing into the lower sheet metal. That is why this build uses a 6-bar hinge system and a support bracket that ties the lower bed back into the chassis at the original seam. The same thinking carries into the engine bay. The tubs, firewall, and surrounding panels are being built to match the look of the Whipple 3.8L Supercharger, while still clearing the hood spring hardware and routing A/C lines cleanly through the firewall. Bead-formed structure, welded seams, and bolt-in mounting points give the bay a finished look without losing serviceability.
Work started on the 1966 Chevy bed by cutting it apart in preparation for a tilt-bed conversion. The goal was not simply to remove the bed from the truck, but to separate it along the factory body line so the upper portion could later hinge open. That seam originally existed as a spot-welded flange running the length of the bedside, and the preferred approach was to leave that split until the entire bedside was loose and easier to handle on its own.
The front bed section came apart first after the bolts were soaked and removed. Other areas were less cooperative. A U-channel structure had to be cut out, and what remained of the carriage bolts also had to be removed. The tailgate itself was relatively straightforward, using two bolts on each side, but the reinforced rear U-channel under the tailgate was much more involved because it was secured by four bolts from the opposite side and additional hidden attachment points.
Disassembly turned into a much bigger job than expected. Considerable effort went into trying to preserve the rear U-channel, the rearmost structural piece beneath the tailgate. The team cut and pried at every visible fastener and attachment point, only to discover that a hidden lap weld was still holding it together. That concealed weld explained why the part refused to come free despite all the obvious bolts having already been dealt with.
After several hard hours, the bed was finally blown apart into separate pieces. With the major structures removed, the next step was to split the bedsides into upper and lower sections by locating and grinding out the factory spot welds along the original seam. Once separated, the body-line cut could continue cleanly through the front and rear lips so the bed could be reconfigured into its new opening arrangement.
The original bed was essentially a conventional pickup box: two bedsides, a front panel, and a drop-down tailgate. That layout would not work for this truck, LockJaw, because the plan is for the bed to scissor open in a manner similar to the hood, but in the opposite direction. To make that possible, the bed has to be split horizontally into two major sections.
The factory seam provided a natural place to divide the structure, but once that seam is no longer permanently spot welded together, the lower portion of the bed loses the support it originally had. That means the redesign is not just about adding hinges. The lower panel must be reinforced and tied into the chassis so it remains rigid instead of flexing at the split line. In other words, the bed conversion requires both a new opening mechanism and a new structural strategy.
Matt explained the chassis-side support concept using CAD. Because the bed is now divided into upper and lower halves, the original lower bed rails can no longer be used in their stock form. A new bracket system is needed to connect the lower bed structure to the Roadster Shop chassis.
The bracket shown in CAD picks up on the frame rail at several mounting points, then arches upward to grab the seam area where the bed originally joined together. That bracket will hold the lower portion of the bed in place and restore rigidity at the split point. Additional stiffeners, not yet shown in the CAD model at that stage, will be added to strengthen the assembly. The approach is similar in principle to the support structure previously built on the underside of the hood for its reverse-opening hinge mechanism.
The upper bed section requires its own framework and a linkage system that allows it to open without colliding with the lower sheet metal left in place. For that, Matt designed a six-bar linkage. In the CAD motion study, the upper bed lifts away from the lower section as it opens, rather than simply rotating backward into surrounding panels. The tailgate moves with the upper structure as part of the opening assembly.
As the bed rises, the main driving link causes the other links to unfold in sequence, producing the desired rotation and lift path. Matt was still refining the geometry, particularly to avoid the driven links going over center. In some mechanisms, slight over-center travel can be useful because it helps lock the assembly in position, but in this case the preferred solution was for the main link to pass over vertical while the driven links stayed out of an over-center condition. The plan also included a spring assist so the bed would lift more easily and remain in a stable open position at shows, rather than dropping unexpectedly.
Once the bed brackets and linkage components are finalized, they will be sent to Sean at Empire Fab for installation on the truck and for completion of the surrounding sheet metal work. That work is happening in parallel with the bed redesign because the project is on a tight schedule leading up to SEMA, where LockJaw is expected to debut in the AMSOIL booth.
At Empire Fab, earlier work had already focused on the transmission tunnel and driveline tunnel. The transmission tunnel was built as a two-piece assembly and metal-finished after welding. The driveline tunnel was extended straight rearward. They intentionally chose not to add beads to that tunnel because they preferred the smooth appearance and wanted visual emphasis to remain on the engine bay.
Attention then shifted to the engine bay, where the driver-side inner fender tub had been laid out and its pieces fabricated. Clearance was built in for the hood mechanism, specifically to work with a factory-style spring arrangement rather than gas shocks. That packaging requirement influenced the shape of the tub and the surrounding structure.
The plan was to design the tubs and firewall together as a coordinated assembly. Once the shapes were finalized, the pieces would be stamped, fully welded, metal-finished, and then bolted into place. Additional detailing could follow after the major structures were complete, but the immediate priority was getting the core forms and mounting strategy resolved.
By the next progress update, both tubs had been made and welded together. The inner beads were completed and trimmed, and the firewall had been formed with matching bead details. A stepped section was added for the rib that provides structure to the core support area. The bead pattern used on the firewall matched the tubs so the engine bay would read as one cohesive design.
To create those bead details, Empire Fab made a custom male-and-female die for the Pullmax. The die profile matched the inside radius needed for the shapes, but after running the parts through the machine, the beads still had to be hand-driven and cleaned up because the dies left the forms too squared off. The bead layout was kept straight and evenly spaced relative to the rib structure, and the shapes were fitted carefully around the air boxes.
An A/C bulkhead was also integrated into the tubs and firewall area so the A/C lines could route across the inner structure, stay away from the tire, and then pass through the firewall cleanly. The pedal assembly had to be modified as well. Material was cut away from the pedal mount area so it would sit flush against the newly beaded firewall. Weld-on cage nuts were spot welded to both sides of the firewall to provide mounting points for the tubs.
The remaining fabrication sequence was clearly defined. After the front tub mounts are completed, the cab will come back off so the firewall and kickback section can be welded into a single piece, metal-finished, and then welded permanently to the cab. After the welds are cleaned up, everything will be reassembled, and attention can shift to the hood cut, which is the next major piece of the overall puzzle.
With the bed now dismantled, the hinge concept modeled, and the engine bay sheet metal nearing completion, the project has entered crunch time. The truck is being built toward a SEMA unveiling in the AMSOIL booth, so every fabrication step now has to move quickly while still fitting into the larger mechanical and bodywork plan.