Fatman Fabrications has long been a trusted name in the custom chassis and suspension industry for classic and modified vehicles. Their Mustang II Stage III Independent Front Suspension (IFS) kits and chassis assemblies are engineered to provide modern performance, improved handling, and a clean stance to vintage cars and trucks. This article explores the key installation steps, design features, and technical specifications of these systems based on real-world installation reports and product documentation.
Overview of Fatman Fabrications IFS and Chassis Solutions
Fatman Fabrications offers a range of suspension and chassis solutions designed for classic vehicles, including 1937–1946 Chevrolet trucks, 1938 Packards, and 1951 Fords. Their Mustang II-based front suspension kits and full chassis assemblies are tailored to fit older vehicles that were originally equipped with outdated or outdated leaf spring systems. These kits are designed to be robust, adaptable, and user-friendly, often including all necessary components for a complete conversion.
A key feature of the Fatman Mustang II Stage III IFS is the integration of polished stainless steel control arms, QA1 coilover shocks, and a power rack-and-pinion steering system. These components work together to provide precise handling, adjustability, and a lowered stance. For vehicles with channel-style frames, Fatman recommends boxing the frame for added structural integrity, especially in the area between the firewall and axle centerline.
Chassis assembly projects often involve disassembly, frame preparation, and reassembly with modern suspension, brakes, and drivetrain components. The installation process is typically carried out by experienced fabricators and includes steps such as trimming the radiator support, aligning the crossmember, and welding in new suspension components.
Key Components of the Fatman Mustang II Stage III IFS Kit
The Fatman Mustang II Stage III IFS kit is a comprehensive solution for upgrading the front suspension of classic trucks. According to the documentation, the kit includes:
- Front Crossmember: A custom front crossmember designed to fit the specific model and year of the vehicle.
- Tubular Control Arms: TIG-welded upper and lower steel tubular control arms for durability and strength.
- Spindles: New spindles to accommodate the modern suspension geometry.
- Coilover Shocks: QA1 single-adjustable coilover shocks for both springing and damping.
- Rack-and-Pinion Steering System: A rebuilt power rack-and-pinion steering system with all necessary mounting hardware.
- G-Tech Tie-Rod Ends: Fatman's exclusive tie-rod ends with a longer tapered shaft for proper alignment.
- Mounting Brackets and Hardware: All necessary brackets and hardware for installation.
These components are designed to work together to provide a modern, adjustable, and durable front suspension system that replaces the original leaf spring setup.
Installation Steps and Technical Considerations
Installation of the Fatman Mustang II Stage III IFS kit involves a series of precise steps to ensure proper alignment, functionality, and performance. Here is a detailed breakdown of the process based on the provided documentation:
1. Frame Preparation and Alignment
Before installing the new suspension, the original suspension must be removed, and the frame must be prepared. The frame is typically stripped of its original components and cleaned. For vehicles with channel-style frames, boxing the frame is recommended to add strength. This involves welding in 1/8-inch hot-rolled plate steel from at least 4 inches inside the firewall forward to 4 inches ahead of the axle centerline.
The frame is then leveled from side to side to ensure proper alignment. A hot rod-style forward rake of 2–3 degrees is recommended, with a typical setting of 2.7 degrees at the "belly" of the frame. A plumb bob is used to establish the front axle centerline, and this line is scribed onto the frame rails and marked with a punch on the outer, bottom, side, and top.
2. Radiator Support and Crossmember Installation
The radiator support or crossmember often requires trimming to accommodate the new suspension components. The area is measured, marked, and trimmed using a plasma cutter and a 36-grit grinding disc. Eye protection is essential during this step. Once trimmed, the crossmember is clamped in place and leveled using a digital angle finder. The crossmember is then MIG-welded to the frame rails for a secure fit.
3. Suspension Components Assembly
With the crossmember in place, the tubular control arms, spindles, and QA1 coilover shocks are assembled. The control arms are aligned with the axle center marks, and the shocks are mounted to provide the desired ride height and stiffness. The team at The Auto Shoppe notes that the coilovers allow for both ride height adjustment and damping control, making it easier to fine-tune the suspension to the vehicle’s weight and driving style.
The power rack-and-pinion steering system is then mounted to the new crossmember using the provided bushings and hardware. This system is critical for providing precise steering response and reducing the effort needed to steer the vehicle, especially at low speeds.
4. Tie-Rod Ends and Alignment
Fatman Fabrications’ G-Tech tie-rod ends are installed to ensure proper geometry when using the boosted camber settings. These tie-rod ends feature a longer tapered shaft, which helps return the tie-rods to their correct position. After installation, the front suspension is aligned to ensure proper toe, camber, and caster settings.
5. Braking and Drivetrain Integration
Once the suspension is installed, the braking and drivetrain components are addressed. In one example, Wilwood aluminum calipers were installed on all four corners, and a Wilwood aluminum master cylinder was plumbed to the calipers using stainless steel lines. The Eastwood tubing bender and flaring tool were used to shape and flare the lines for a secure fit.
For the drivetrain, an EcoBoost V-6 engine was mounted to custom motor mounts, and a Dynotech driveshaft was used to connect to the Ford 9-inch rear end. Due to space constraints around the turbo exhaust and oil filter, the power steering system was omitted, but the rack-and-pinion system remained.
6. Final Assembly and Testing
After all components are installed, the vehicle is test-driven to ensure proper function and performance. Adjustments may be made to the coilovers for ride height and damping, and the steering system is tested for responsiveness and accuracy. Final checks include verifying the brake system, suspension geometry, and drivetrain alignment.
Technical Advantages and Design Philosophy
Fatman Fabrications' chassis and suspension systems are built with a focus on strength, adjustability, and modern performance. Key advantages include:
- Adjustable Coilover Shocks: The QA1 coilovers allow for precise tuning of ride height and damping, making it easier to achieve the desired stance and handling.
- Improved Geometry: The Mustang II-based design provides a more modern suspension geometry compared to original leaf spring setups, leading to better weight distribution and cornering performance.
- Modular Components: The use of tubular control arms, spindles, and crossmembers allows for easy customization and replacement if needed.
- Compatibility with Modern Components: The kits are designed to work with modern power racks, disc brakes, and drivetrains, making it easier to integrate high-performance upgrades.
The design philosophy behind these systems emphasizes simplicity, durability, and adaptability. For example, the forward rake of 2–3 degrees is designed to give the vehicle a more aggressive stance while maintaining structural integrity. The use of stainless steel control arms and aluminum shocks not only improves aesthetics but also reduces corrosion and wear over time.
Real-World Applications and Case Studies
Several real-world installations of Fatman Fabrications kits have been documented in detail, showcasing their versatility and effectiveness.
1946 Chevrolet Truck Conversion
In one case, a 1946 Chevrolet truck was converted using the Fatman Mustang II Stage III IFS kit. The truck was originally equipped with a leaf spring front suspension, lever-style shocks, and drum brakes. After installation of the new suspension, the vehicle was equipped with QA1 coilover shocks, a power rack-and-pinion system, and Wilwood disc brakes. The frame was boxed for added strength, and the crossmember was trimmed and welded into place.
The result was a significantly improved stance and handling. The truck retained its classic appearance while benefiting from modern suspension technology. The team at The Auto Shoppe noted that the installation process was straightforward and that the components were easy to align and adjust.
1938 Packard Chassis Upgrade
Another example involved a 1938 Packard that was upgraded with a Fatman frame stub kit, an LS engine, and a 4L80E transmission. The rear suspension was replaced with a Ford 9-inch rearend and a Fatman four-link system. Sway bars were added to both the front and rear for improved stability.
This project highlighted the adaptability of Fatman Fabrications’ products. The team was able to integrate modern suspension, braking, and drivetrain components into a classic vehicle, resulting in a high-performance street rod with improved handling and reliability.
1951 Ford Chassis Assembly
A 1951 Ford was prepared for the 2013 AMSOIL/Street Rodder Road Tour using a Fatman Fabrications chassis. The chassis was built from scratch, with the frame being boxed and painted. The front suspension included polished stainless steel control arms and QA1 coilovers, while the rear was equipped with a Ford 9-inch rearend and a four-link setup.
The vehicle was also fitted with a twin-turbo EcoBoost 3.5L V-6 engine and a custom exhaust system. The final assembly process included painting the frame, installing the engine and suspension components, and test-driving the vehicle to ensure proper function.
Additional Services and Support
Fatman Fabrications also offers a full-service rod and repair program for customers who prefer to have their kits installed by professionals. This allows customers to purchase a kit and have it installed by the engineers and fabricators who designed it, ensuring a high-quality result. This service also serves as a form of research and development, as the team gains hands-on experience that can be passed on to customers who choose to install the kits themselves.
In addition to kits and installation services, Fatman Fabrications provides detailed instructions and support for DIY enthusiasts. This includes technical documentation, installation guides, and customer support to help users through the process. The company’s commitment to quality and customer education has made it a preferred choice for many in the street rod and hot rod communities.
Conclusion
Fatman Fabrications’ Mustang II Stage III IFS kits and chassis solutions offer a comprehensive and modern approach to upgrading classic vehicles. By integrating polished stainless steel control arms, adjustable coilovers, and rack-and-pinion steering, these systems provide improved handling, adjustability, and aesthetics. The installation process is designed to be straightforward, with all necessary components included and detailed instructions provided.
Whether for a 1937–1946 Chevrolet truck, a 1938 Packard, or a 1951 Ford, Fatman Fabrications’ products are engineered to meet the demands of both performance and style. Their commitment to quality, durability, and adaptability makes them a top choice for enthusiasts looking to modernize their classic rides without sacrificing their original character.