Welcome back, builders and gearheads! In Part 3 of our 1967 International Loadstar build, we’re tackling a key piece of the puzzle — fabricating a custom firewall and engine cover to fit the cab swap onto a modern 2012 Chevy Express van chassis.
This isn’t your typical show truck build. We’re going DIY, hands-on, and fast — with an aggressive goal of getting this thing running in under a week. Let’s dive into what went down.
Precision Meets Cardboard: The CAD You Didn’t Expect
No CNC, no 3D scans — just Cardboard Aided Design (CAD), a Sharpie, and a razor blade. That’s how we mapped out the firewall and trans tunnel (okay, engine tunnel) to ensure tight tolerances while maintaining pedal clearance and steering column access.
🔧 Pro Tip: We marked every seam and panel with alignment indicators to make transferring the shapes to metal clean and accurate.
Editor’s Choice
Laying the Foundation: Sheet Metal Fabrication
Using 14-gauge steel for the firewall gave us a perfect balance of rigidity and workability. A digital angle finder helped measure exact bends, while our trusted shear and brake made quick work of the panels.
We installed everything using Clecos and spot welds before tack-welding the firewall into place. Some finesse with a hammer ensured perfect conformity to the truck’s floorpan.
🛠️ Tip: 14-gauge sheet metal is the sweet spot for firewall fabrication — stiff enough for durability, but workable with standard shop tools.
Firewall, Meet Engine Cover
Once the firewall was fitted, we built a fully removable engine cover out of sheet metal — again, templated from cardboard. To keep it easy to service, we added weld-on brackets and threaded mounting points, ensuring it bolts in tight but comes out clean when needed.
We also pre-planned for a rubber gasket seal all the way around the engine cover for a better fit and heat control.
Recent Posts
Upgrades Along the Way
While the cab was off, we handled a few key updates to the engine:
- 🔄 New water pump & thermostat
- 🔁 Fresh belts and pulleys
- 🧼 Cleaned and prepped mounting surfaces
Why? Because once this cab goes back on, we want zero headaches down the road.
Final Welds and Fitment
We lifted the cab off for one final time and fully welded the firewall and tunnel seams, smoothing everything out with a flap disc and grinder. The goal here isn’t show-truck perfection — it’s solid, smart fabrication that performs.
🎯 Reminder: This Loadstar isn’t a trailer queen. It’s a custom daily-driven shop truck built to look good and go hard.
What’s Next: Steering, Brakes, and Pedals
With the firewall in and the engine bay cleaned up, next on deck is:
- Installing the brake booster and pedal assembly
- Running the gas pedal and linkages
- Setting up the steering column
We’re documenting every step in this fast-paced series, so if you’re loving the process, make sure to subscribe to StealthBuilt on YouTube and follow us on Instagram.
Want to Build Your Own?
If you’re working on a cab swap project or just love fabrication content, drop your questions in the comments below. We love hearing from other builders and sharing tips from the shop floor.
👇 Drop your thoughts in the comments:
- What engine swaps are you working on?
- Would you have kept the van’s firewall or gone full custom like we did?
- Anyone else obsessed with cardboard templates?
🔧 Tools We Used in This Episode:
- Milwaukee cordless angle grinder
- Digital angle finder gauge
- Sheet metal brake & shear
- MIG and TIG welders
- Clecos & panel clamps
Stay Tuned for Episode 4
In the next episode, we’ll be installing the brake system, steering linkage, and throttle setup. You don’t want to miss it.
📌 Subscribe on YouTube
📲 Follow @StealthBuilt on Instagram & TikTok
🛒 StealthBuilt gear and merch available soon
