Use this section to find performance parts for 1988-1998 Chevy and GMC OBS (old body style) trucks and SUVs from Hedman Hedders and Trans-Dapt Performance Products. This category includes headers for many original factory-engine combinations, along with components for LS engine-swap projects, valve covers, differential covers, throttle body spacers, and even a few chrome and powder-coated engine accessories. Whether you are upgrading a stock truck, building a street-performance rig, or installing a totally different engine, the products in this section are designed around the fitment requirements of this popular GM truck generation.
Hedman offers headers for factory-equipped Chevy and GMC OBS applications. The position of the engine on these trucks was offset from the factory. The OBS truck headers in this section are designed for this offset engine position. They are not designed for use on older GM trucks with the engine centered between the frame rails. Depending on the vehicle and engine combination, available products may include mid-length, or long-tube headers for two-wheel-drive and four-wheel-drive trucks and SUVs. Choosing the correct header requires matching the product to the vehicle year, model, engine, transmission, drivetrain, emissions equipment, cylinder-head configuration, and any modifications that could affect available clearance. Not looking for OBS truck headers? Just click here to browse our complete selection of Hedman Hedders.
In addition to factory configuration headers, Hedman Hedders and Trans-Dapt Performance also offer LS swap headers, engine mounting components designed to install the GM LS engine and route the exhaust within the 1988-1998 Chevy truck or SUV chassis. Because engine position affects header clearance, oil-pan clearance, transmission alignment, accessory placement, steering clearance, and exhaust routing, mounts and headers should be selected as coordinated parts of the complete swap combination. Explore our LS swap headers, LS engine swap mounts, and LS swap kits for trucks.
• Factory-engine and engine-swap coverage: This category includes products for many original Chevy and GMC engine combinations as well as parts for LS engine-conversion projects.
• Application-focused header designs: Hedman's headers are developed around specific vehicle, engine, drivetrain, and chassis combinations rather than relying on a one-size-fits-all approach.
• Coordinated LS swap components: Hedman LS swap headers and Trans-Dapt engine mounting products can be selected together to help establish proper engine placement and exhaust clearance.
• Parts for a wide range of builds: Product options may support stock replacement projects, daily drivers, work trucks, complete restoration projects, street-performance trucks, and engine swaps.
• Multiple drivetrain configurations: Available applications may include both two-wheel-drive and four-wheel-drive vehicles, with product-specific fitment notes identifying important restrictions.
• Experienced technical assistance: Hedman Hedders has been manufacturing headers for over 70 years. Trans-Dapt Performance has been building performance products since 1959. With such extensive product history, Hedman's technical support staff can help review the vehicle, engine, drivetrain, cylinder heads, and modifications when additional fitment guidance is needed.
What does OBS mean when referring to Chevy and GMC trucks?
OBS is a commonly used enthusiast term meaning “Old Body Style.” On this page, it refers to the 1988-1998 generation of Chevrolet and GMC full-size trucks and related SUV applications. Individual part fitment may cover only certain models, years, engines, or drivetrain configurations within that broader vehicle family.
Does this category only contain LS swap parts?
No. This category includes headers and performance components for trucks and SUVs retaining factory-style engine combinations, as well as products for engine swaps. LS swap headers and engine mounts are an important part of the selection, but they are only one portion of the overall category.
How do I choose the correct headers for my OBS truck?
Match the header to the exact vehicle year, model, engine, transmission, two-wheel-drive or four-wheel-drive configuration, cylinder heads, emissions equipment, and relevant modifications. Review all product-page application notes and restrictions before ordering. Headers listed for OBS trucks differ from headers listed elsewhere on this website for 1967-1991 Trucks. Headers listed broadly for 1967-1991 trucks and SUVs
Will the same headers fit both two-wheel-drive and four-wheel-drive trucks?
Not necessarily. Four-wheel-drive trucks may have front differentials, transfer cases, crossmembers, steering components, or suspension parts occupying space needed by the headers or exhaust system. Only use a header on a four-wheel-drive application when that configuration is specifically included in the product fitment information.
Why does the engine mount selection matter when choosing LS swap headers?
The engine mounts establish the position of the LS engine within the chassis. That position directly affects header, firewall, steering, oil-pan, accessory-drive, transmission, and exhaust-system clearance. Using mounts and headers intended to work with the same application can reduce unnecessary fabrication and fitment problems.
Can vehicle modifications affect header fitment?
Yes. Suspension changes, transmission swaps, aftermarket cylinder heads, relocated accessories, custom steering components, frame modifications, and previous exhaust work can change the available clearance. Modified vehicles should be inspected carefully during installation.
Who can help me verify which parts fit my truck?
Review the application notes and specifications on the individual product page first. For additional assistance, contact Hedman technical support at (562) 921-0404 with the vehicle year, model, engine, transmission, drivetrain, cylinder-head information, and a list of relevant modifications.
Important Fitment Note: The 1988-1998 Chevy and GMC OBS vehicle family includes numerous engine, transmission, drivetrain, chassis, emissions, and body configurations. Product fitment is determined by the specific application information shown for each part, not by the OBS designation alone. Always verify the complete vehicle and engine combination before ordering. Engine swaps and modified vehicles may require additional parts, exhaust work, or fabrication.
