Nifty ’90s – A Guide to Parts for 1988-98 Chevrolet and GMC OBS Trucks
We’ve been seeing a lot of good-looking, very-well-built GM OBS trucks at local shows, on social media, and during Meguiar’s All American Sundays at Goodguys events this year. These trucks are the generation after the wildly popular squarebody series, which ended its long run in 1987. With its debut as a 1988 model in early ’87, this next generation of trucks had an all-new look with rounded lines for a bit more efficiency, fuel injected engines with overdrive transmissions, and much roomier interiors. Also, note the absence of a side vent window!
But what exactly does OBS stand for you ask? Strangely enough, it means Old Body Style (or to some, Original Body Style). This makes no sense to most people over 40, but it name has stuck. The OBS name starts from the internal GM code, GMT400, given to the all-new model truck which was replaced by the GMT800 in 1999. Thus the “Old Body Style” moniker for today.
This model was in production from 1988 through 1998, with a few years between to cycle in the SUVs and heavy-duty trucks. Models were available in a number of configurations including fleetsides in single, extended and crew cabs, along with a stepside single cab, in both 2- and 4WD.
Throughout their production run, just like their predecessors, the OBS trucks went through mild revisions such as moving to composite headlamps, different trim styles. and special packages such as the W/T 1500 (Work Truck) and the 454 SS options. In short, there’s a truck for just about everyone out there from standard cabs to crew cabs and a lot of different options.
Speaking of options, it’s great to see so many manufacturers jumping into the OBS market with new products to help restore and modify these pickups. From interior restoration components to the all-important suspension upgrades to achieve the right stance, companies are on the ball for OBS owners. Following is a gathering of cool parts to check out and we’re betting that in another six months there will be even more!
Being able to upgrade the safety of your pickup while adding modern, cool looks is a great combination and is exactly what you get with a set of Baer brakes. For serious braking performance the company offers its proven six-piston caliper mounted over a two-piece 14-inch rotor that has been slotted, drilled, and plated for great looks and performance. The billet aluminum hubs are assembled and packed with Redline synthetic grease and pre-assembled on a modified 2-inch drop spindle.
The rotors are assembled with NAS-grade stainless hardware and Baer also supplies stainless braided brake hoses. The six-piston caliper has DOT-compliant dust and weather seals and uses the popular D0731 pad. To complement the front system, Baer offers a 13- or 14-inch rear kit. Baer’s kits are compatible on trucks with or without factory Anti-Lock Brake Systems (ABS).
Who doesn’t love a low, mellow exhaust note to give their truck a bit more attitude, while still keeping things quieter from the inside. Flowmaster offers a direct-fit Force II Cat-back exhaust system for ’88–’92 trucks, from short beds to long beds equipped with a 5.7L engine and slip-fit converter.
The exhaust is constructed from 3-inch mandrel-bent aluminized steel tubing and directs the fumes through a 70 Series Big Block II muffler for a deep, mellow tone. The tailpipe is supplied with factory-style hangers and exits to a single-out-side (SOS) which is perfect if you tow a trailer. Your engine will exhale easier, so you’ll see an improvement in performance as well as the tone of your truck.
Put a Stick In
If you prefer to stir the gears in your sporty OBS, American Powertrain now offers its ProFit line of five- and six-speed updates. The systems are available with the new Tremec TKX five-speed or the Magnum six-speed coupled with all of the parts needed to successfully get the job done. No mods are required to the tunnel and there are shift positions available for bench and bucket seats.
Both kits can be used with the stock crossmember with only a few holes needing to be drilled in the frame and are compatible with LS swaps as well. A stock hydraulic clutch cylinder will work, or you can use one of American’s Hydramax Hydraulic clutch slaves. The kits are complete including an electronic speed sensor solution, pilot bearing, reverse light wiring, driveshaft, and shift knob. They also offer a Pro-Touring series upgrade which includes a balanced aluminum driveshaft and White Lightning shifter to handle on-track abuse.
Grip and Stop
Looking to drop your C1500 while improving the braking performance? Wilwood’s C1500 Iron ProSpindle is just what you need to lower your two-wheel-drive pickup, Blazer, or Suburban while accepting one of Wilwood’s brake systems. The spindles are cast steel with integrated steering arms for the ’88-’98 models and have a traditional bearing snout that support’s Wilwood’s kit-specific hubs in both 5×4.75- and 5×5-inch bolt circles.
The radial-mount caliper brackets allow for the installation of Wilwood’s popular Superlite 6R and Aerolite 6R brake kits that feature forged aluminum hubs with rotor diameters from 12.19- to 14-inches. You can select a plain face rotor, step up to an SRP drilled and slotted model, or choose their Spec37 curved vane design. Whatever option you choose, it will be compatible with the factory ABS system.
Clearance that’s Cool
Dropping your truck down for a killer stance with big wheels is cool, but having the front tires rub and bump around corners is not. Have no fear, as Slosh Tubz is here to help you gain clearance with their unique line of inner fender tubs for OBS trucks. Their latest design is their Mild Faux Metal Tubz that look like metal thanks to a bead-rolled design but are actually high-strength fiberglass. The engine side is finished in a semi-gloss black gelcoat that looks great but can easily be scuffed and shot with your favorite color.
With a set of Faux Metal Tubz you’ll gain about 2-inches of clearance right at the crown of the fender, as well as another 2-inches on the outside edge. The biggest gain, however, is the inside edge which is about 4.5-inches more space so you can get a big set of meats up under the front! Slosh Tubz makes certain that their kits will clear the factory A/C system as well as any wiring.
Even if you’re cruising with the factory engine and EFI system of your OBS truck, there are a number of engine upgrades that will help perk up its performance. Edelbrock developed a Performer intake manifold that easily bolts right on to a 5.0L or 5.7L and accepts the factory throttle body fuel injection system. (There’s also an intake available for ’91-’95 big blocks!)
The intake manifold is cast at Edelbrock’s foundry in North Carolina and the finished piece features a 4.40-inch TBI pad (about .25-inch taller than stock). The port exits are 1.13×1.87-inch and with years of intake manifold design experience, you can be sure these intakes will improve the performance of your truck. If you buy one of Edelbrock’s performance packages that includes the intake, aluminum heads, and a cam, you’ll also receive a specially calibrated computer chip to make the best of your new combination.
All American Billet
Hinges that Work
Factory hood hinges were developed with one goal; functionality. Sleek, cool looks were definitely not a part of the original plan for hinges. Fortunately for us, function and good looks are exactly what All American Billet lives for and their new hood hinges for OBS trucks illustrates this point!
The billet hinges are machined from 6061-T6 aluminum for great strength and engineered to last. Sturdy stainless steel gas struts are used in conjunction with large bearings for consistent opening and closing action. The hinges are supplied with stainless steel hardware and are available in machined, polished or black anodized finishes. Be sure to check out their Billet Door Jamb Vents as well.
Summit Racing Equipment
Looking to free up the exhaust flow and while gaining a bit more rumble from behind your truck? Summit Racing offers a number of bolt-in exhaust systems for OBS trucks. Each system connects to the factory catalytic converter and features aluminized steel tubing that is mandrel-bent for a nice fit and flow.
Every kit is supplied with clamps, hangers, and hardware to complete your installation. Summit offers kits in rear- and passenger-side exit configurations depending on the application. Systems are available for short or long beds and include a performance muffler such as the dual outlet version shown in their kit PN 688350.
Old is New Again
McGaughys was deep in the midst of lowering kits for OBS trucks when they were new! Their most popular system is the go-to 4-/6–inch drop kit which settles these trucks down to an ideal stance with great looks and handling to match.
The McGaughys drop kit is based on their own USA-made 2-inch drop spindles with 2-inch drop coils for the front with a 6-inch flip kit and C-notch kit in the rear. The rear kit includes flip plates, axle pads, the plates and hardware. Shocks are available separately, and they’re ready to help you select a pair to meet your driving goals. Each drop system is designed so it can be installed by an average truck guy on a weekend with typical garage tools.
On average, your OBS truck is right at the three-decade age which means most of the rubber and foam pieces around the doors and windows are flaking apart, torn, and failing to keep the interior quiet and sealed. Fortunately, the good folks at Steele Rubber already offer a six-piece Door Window and Beltline Set.
The entire Steele kit will help you restore your truck to a like-new, wind- and rattle-free ride thanks to their years of experience in developing restoration seals and window channels. This kit is supplied with a new beltline molding as well as the glass run channels for each door. Steele uses high quality materials to develop each component to the original specs for a superior fitment and seal.
So, you’re looking to update the stance and road worthiness of your OBS project? RideTech was convincing everyone about the qualities of air suspension when these trucks were new and have continued to develop a catalog of new suspension products for these trucks over the years. They now offer three complete packages for stance and handling performance as well as a number of bolt-on upgrades including their Strong Arms, HQ Shocks. and sway bars.
The StreetGrip Drop-and-Shocks system provides spindles, lowering sprigs, and a rear leaf flip kit highlighted with Fox single-adjustable monotube shocks. For more control and tunability, RideTech offers a coil-over or air suspension system that includes tubular arms and an innovative three-link rear system to really step up the handling performance of an OBS truck.
Converting to Coil-Overs
If you’re looking to be able to adjust the ride height and handling performance of your truck, QA1 offers a complete bolt-in coil-over conversion kit for OBS trucks. The front suspension delivers a drop up to 6-inches and includes their tubular control arms and spindles that provide increased camber and caster for better handling, while their adjustable coil-overs allow you to set up the system for your ultimate driving goals.
The rear system was designed to be installed without removing the bed and requires no welding! The unique torque arm design removes the inherent binding of the stock setup and provides from 4- to 7-inches of drop. Each suspension system is made in the USA, powder-coated for durability, and ready for installation including all-new fasteners.
When we think of a modifying the stance of an OBS truck, generally it involves dropping it on the ground, but don’t forget about how cool these trucks can look with a little lift too! ReadyLIFT offers a number of ways to get your truck lifted to fit a taller, heftier tire underneath. One of the easiest and safest ways to gain 1.5-inches on your OBS is with their Torsion Key Lift Kit.
Torsion bars are based on the twisting resistance force in a similar manner of that of a coil spring. The GM four-wheel-drive trucks have one end of the torsion bar fixed to the frame’s crossmember with the other connected to the lower control arm. ReadyLIFT’s Torsion Key mounts in between and holds the torsion bar at the preferred height and installs securely to the flats of the bar for a tight, secure grip. The keys are formed from forged steel for extreme strength and machined for a precise fit providing accurate and safe adjustment.
The stylish new OBS truck was critical in establishing the sport truck movement of the early-’90s, which may be even bigger today. The original interior, by today’s standards, is kind of lacking in style and comfort, but that is where TMI Products comes to the rescue.
TMI has brought its interior upgrades and modern styling to the OBS platform and can instantly transform your truck with a stunning and comfortable interior. Their website provides an almost infinite level of customization with seats, consoles, door panels, and headliners to match any style and vision. Best of all, once it’s ordered, the parts show up on your doorstep ready to install with a direct fit into your truck!
One of the best upgrades you can make to your interior comes down to its instrumentation and Dakota Digital is here to help with an all new HDX package for the OBS platform. Not only will you be gaining a tachometer, but there is also a large, full-color message center which allows for auxiliary readings. Plus, the entire assembly interfaces with just about any drivetrain you choose for your OBS.
Each HDX system allows you to select independent illumination colors for the gauge readings and needles, as well as the message centers. Calibration and personal settings are set with the capacitive-touch buttons or through a Bluetooth app! Installation is simplified with a central control box and connects to vehicle-harness-sourced signals for less wiring and improved ease.
Speedway Motors is ready to help you achieve the appearance and performance you want for your OBS Truck. They offer the full line of Belltech suspension kits for pretty much every cab size, model, and dually variation available.
Belltech’s very first product was produced for a GM vehicle back in 1983 and the product line has since grown to offer suspension parts and systems for most trucks. They offer shocks, sway bars, control arms, and complete kits to achieve the handling you desire and Speedway Motors is ready to get the system in your hands.
Steel and Dash
If you’re working on an OBS project, chances are you’ll be needing to replace some sheet metal due to damage, rust, or age. The good news is that LMC Truck has a full line of high-quality steel panels including cab mounts, rocker panels, floor pans, a variety of bed panels and even cowl induction hoods. The steel panels are sealed in an Electro Deposit Primer (EPD) coating to ensure that they remain rust free until you’re ready for prep and paint.
Also, noting the growing popularity of these ‘new’ classic trucks, LMC Truck set out to develop a new Dash Panel assembly to help make your interior look new. The dash uses heat-resistant thermoplastic compounds to resist shrinking and fading and is ready to paint to match your interior. This exclusive product is supplied complete with the new plastic shell installed with rivets and screws to a complete zinc-coated metal frame just like when they were new.
Great music goes hand-in-hand with fun cruising, and Retro Manufacturing has a great way to upgrade the stereo in your OBS truck while still maintaining its OEM looks. The RetroSound Santa Cruz stereo is designed specifically for 1988-94 GM trucks and is now available in three different feature sets to meet your music needs.
The basic Santa Cruz Laguna model has an AM/FM tuner, 275-watt amplifier, and rear auxiliary inputs. The Hermosa model steps up to a 300-watt amp and has Bluetooth connectivity, a rear-mounted USB port, and a 32,000-color display. And the Long Beach model features a second USB port, iPod and iPhone compatibility, dedicated subwoofer output, and is Sirius SM-ready. No matter which model you choose, you’ll have modern music capabilities and features with a classic OEM appearance that perfectly fits your OBS dash.