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C1500 / K1500 OBS LS swap
A typical C1500 / K1500 OBS LS swap runs about $7,000–$12,000 in parts ($4,000 on a budget), and the big decision is where the engine sits: the choice that matters is 2WD vs 4WD, since 2WD long tubes won't clear a K1500.
Last updated
Chevrolet/GMC · 1988–1998Swap kits verifiedGMT4001 parts list
LS Gen III/IV swap — moderate
1988–1998 GM OBS C/K 1500/2500 LS swap: Dirty Dingo slider mounts (2WD/4WD), adjustable 2WD trans crossmember, AC brackets.
Parts and steps for the C1500 / K1500 OBS
Every part option we know for each stage of the swap, plus 0 sourced facts and 9 owner questions. Open a step, start with our pick, and check all the options. Plan your exact combination →
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Before you buy
- Engine choice Verify yourself
Decide which engine fits your power goal and budget, and confirm the exact engine by its RPO or the 8th VIN digit before you pay. - Mounts, crossmember & oil pan Partly sourced
Decide where the engine sits (kit mounts or custom), then measure from the pan rail to the crossmember and to the ground before you choose an oil pan. - Transmission & driveline Partly sourced
Decide which transmission handles your torque and how it will be controlled, then plan the crossmember, driveshaft length and flexplate or bellhousing to match. - Accessories & cooling Verify yourself
Decide one accessory drive spacing, and match the balancer, water pump and brackets to it. Then check fan, hose and hood clearance. - Wiring, computer & tune Verify yourself
Decide a harness and computer that match your engine's crank signal (24x or 58x) and throttle (cable or drive-by-wire), and plan the tune, including VATS.
Biggest gap: engine choice. Owners ask about it a lot (4 questions), but we have few sourced facts for this vehicle yet.
Parts we know for this vehicle: 34 options across 10 of 10 categories.
What it costs: budget build about $4,000; typical build $7,000–$12,000 (parts, not labor, prices as of 2026-10-01).
6.0 or rebuilt 5.3, AZ Pro LS swap kit ($1,175), Speed Eng 1-7/8 headers + X-pipe ($685), Holley Terminator X, Speed Eng oil pan, aluminum radiator w/ fans, Dirty Dingo A/C bracket ($250), NBS master upgrade, dyno tune.
Required parts priced so far (2WD version): $244.99. We have no prices yet for the other version of this vehicle. (required parts on this parts list that have a listed price; parts only: engine, transmission, wiring and labor are extra. Build the full budget →)
Tags: Verified on our parts list or confirmed on the maker's page for this vehicle · Listed the vendor's catalog names this vehicle · Community from owners' builds and small sellers.
Parts and notes for one drivetrain only are labelled 2WD or 4WD; the switch in the step bar hides the other one.
Beta We're still fixing fitment as owners report it. Double-check parts before you buy. See what's new →
1Engine choicePick the engine, then confirm exactly which one it is
We don't have notes for this step on this vehicle yet, so measure and confirm with the part maker before you buy.
Why this step matters: 4 of 9 owner questions about this vehicle
- LQ9 swap in a 1997 Z71 GMT400 - what does it take?
- Vortec 383 or LS swap for a GMT400 tow pig/daily driver?
- 88-98 OBS LS swap mounts — Dirty Dingo vs TransDapt vs Moroso?
- Finished 1999 OBS C1500 LQ9 6.0 swap — what was the combo?
More: Engine & donor finder · Making power
Ready for the next step when you know which engine you're using and have confirmed it by its RPO or VIN.
Next: mounts, crossmember & oil pan →2Mounts, crossmember & oil panSet where the engine sits, then pick a pan that clears · 4 parts
Mounts & swap kits
4 options · $20–$200Why you need it: The mounts set where the engine sits, and that decides oil pan, header and driveline fit. OBS trucks take simple bolt-in mounts. The choice that matters is 2WD vs 4WD: 2WD long tubes won't clear a K1500, and the Holley 302-1 or a low-profile swap pan clears the crossmember. More: engine mounts and swap kits.
Our pick and alternativespick + 2 of 4
We have not confirmed this part on this vehicle yet. If you installed it, tell us what you used and why.
Compare 4 mount & swap kit options
| Maker / product | Part # | Price | Fits / notes | Where | Status |
|---|---|---|---|---|---|
| Dirty Dingo 2WD LS Slider Engine Mounts Verified Our pick · for 2WD only 2WD | DD-2550C | for 2WD only | Direct from Dirty Dingo | ||
| Dirty Dingo 4WD LS Slider Engine Mounts Verified 4WD | DD-2575-4 | for 4WD only | Direct from Dirty Dingo | ||
| ICT Billet Motor Mount Rubber - SBC 4wd 88-98 Chevy Truck Listed 4WD | 551069-0E-3H4W | $20 2026-09-29 | for 4WD only Unconfirmed Confirm this We have not confirmed this part on this vehicle yet. If you installed it, tell us what you used and why. | Check price & fitment | In stock |
| Stone Fab LS motor mount kit 88-98 GM truck / 92-99 SUV Listed | — | $200.00 2026-10-01 | 1988-1998 GM truck / 1992-1999 SUV | Direct from Stone Fab | In production |
Oil pan
3 options · $239.99–$264.99Why you need it: The pan has to clear the crossmember, the ground and, on a 4x4, the front differential. More: oil pan guide.
Options3 options
Compare 3 oil pan options
| Maker / product | Part # | Price | Fits / notes | Where | Status |
|---|---|---|---|---|---|
| Holley LS retrofit oil pan Listed | 302-1 | $239.99 2026-10-01 | 1988-1998 C1500/K1500 (OBS) LS swap; GM rear-wheel-drive applications originally equipped with a small- or big-block Chevy and traditional rear sump oil pan Doesn't fit: A-Body or G-Body applications (use 302-2 or 302-3) | Buy | In production |
| Speed Engineering LS swap oil pan Listed | 26-1039 | $264.99 2026-10-01 | 1988-1998 C1500 LS swaps for 2WD only | Direct from Speed Engineering | In production |
| Speed Engineering Low-profile LS swap oil pan Listed | — | $264.99 2026-10-01 | 1988-1998 C1500 LS swaps (lowered trucks) for 2WD only | Direct from Speed Engineering | In production |
Steering
1 option so farWhy you need it: The engine and headers have to clear the steering shaft and box, and some swaps need a new shaft or box to make room. OBS bolt-in mounts keep the stock box clear; the job is plumbing the LS pump to it, which the Pro Performance 88-98 truck line kit does. More: steering shaft and box clearance.
Options1 option
Compare 1 steering option
| Maker / product | Part # | Price | Fits / notes | Where | Status |
|---|---|---|---|---|---|
| Pro Performance Power Steering LS Plumbing Kit 88-98 GM truck / 92-99 SUV Listed | — | 1988-1998 GM truck / 1992-1999 SUV | Direct from Pro Performance | In production |
Only 1 option found so far for the C1500 / K1500 OBS. Know another? Tell us →
Brakes & booster
2 optionsWhy you need it: A big cam can leave too little vacuum for the booster, and some swaps leave no room for one. A vacuum-booster OBS truck needs a check valve that adapts the LS 1/2 in vacuum port to the booster. More: vacuum booster or hydroboost?
Options2 options
We have not confirmed this part on this vehicle yet. If you installed it, tell us what you used and why.
We have not confirmed this part on this vehicle yet. If you installed it, tell us what you used and why.
Compare 2 brake & booster options
| Maker / product | Part # | Price | Fits / notes | Where | Status |
|---|---|---|---|---|---|
| GM (NBS) OBS-to-NBS master cylinder upgrade Community | — | $99.97 2026 (Laurenceville Garage) | 1988-1998 OBS trucks Unconfirmed Confirm this We have not confirmed this part on this vehicle yet. If you installed it, tell us what you used and why. | parts stores | In production |
| GM Brake booster check valve for LS vacuum port Community | 15823207 | Vacuum-booster OBS trucks (adapts LS 1/2in port to booster) Unconfirmed Confirm this We have not confirmed this part on this vehicle yet. If you installed it, tell us what you used and why. | GM dealers / parts stores | In production |
Kit-specific notes1 note
- 2WD and 4WD use different mounts (Dirty Dingo DD-2550C vs DD-2575-4).
Everything else1 note
- LT variants of the mounts exist.
Why this step matters: 1 of 9 owner questions about this vehicle
- What oil pan, accessories, and manifolds should be used for an LS1 swap into a lowered OBS C1500 with a 4/6 drop?
More: Mounts & swap kits guide · Oil pan guide · Steering clearance guide
Ready for the next step when you've picked where the engine sits and an oil pan that clears it.
Next: transmission & driveline →3Transmission & drivelinePick the transmission and how it shifts, then the parts behind it · 3 parts
Transmission adapter & clutch
2 optionsWhy you need it: An LS needs its own bellhousing or adapter and the right flexplate or flywheel, and an electronic transmission needs a computer to shift it. More: transmission guide.
Options2 options
We have not confirmed this part on this vehicle yet. If you installed it, tell us what you used and why.
We have not confirmed this part on this vehicle yet. If you installed it, tell us what you used and why.
Compare 2 transmission adapter & clutch options
| Maker / product | Part # | Price | Fits / notes | Where | Status |
|---|---|---|---|---|---|
| GM Performance Flexplate spacer kit for early automatics Listed | 12563532K | LS to TH350/TH400 and other early automatics Unconfirmed Confirm this We have not confirmed this part on this vehicle yet. If you installed it, tell us what you used and why. | GM Performance dealers | In production | |
| Amazon/aftermarket TH400 crank spacer adapter Listed | 12563532 | LS to TH400 in OBS trucks Unconfirmed Confirm this We have not confirmed this part on this vehicle yet. If you installed it, tell us what you used and why. | Buy | In production |
Crossmember
3 options · $200–$244.99Why you need it: The transmission mount usually moves, and the crossmember sets the driveline angle. The Suspension Engineering 2WD OBS crossmember is built to clear its X-pipe, and PSI sells an adjustable 1988-98 2WD automatic crossmember. More: getting driveline angles right.
Our pick and alternatives3 options
We have not confirmed this part on this vehicle yet. If you installed it, tell us what you used and why.
Compare 3 crossmember options
| Maker / product | Part # | Price | Fits / notes | Where | Status |
|---|---|---|---|---|---|
| PSI Conversion 88–98 Adjustable 2WD C1500/C2500 Automatic Transmission Crossmember Verified Our pick · for 2WD only 2WD | (crossmember) | $244.99 2026-09-28 | for 2WD only | Direct from PSI Conversion | |
| ICT Billet Transmission Crossmember - 88-98 C1500 Silverado Listed | CM-88-98-C1500 | $200 2026-09-29 | for 2WD only Unconfirmed Confirm this We have not confirmed this part on this vehicle yet. If you installed it, tell us what you used and why. | Check price & fitment | In stock |
| Suspension Engineering Transmission crossmember (OBS) Listed 2WD | — | 1988-1998 C1500 2WD with Speed Engineering X-pipe for 2WD only | suspensionengineering / retailers | In production |
Driveshaft
2 options · $54Why you need it: A different transmission is almost always a different length, so plan on a custom-length driveshaft. Bolt-in mounts keep the stock spot, so length changes only with the transmission; the 3-bolt OBS diff flange may need an adapter to take a 1350 U-joint yoke. More: driveshaft length and angles.
Our pick and alternatives2 options
We have not confirmed this part on this vehicle yet. If you installed it, tell us what you used and why.
Compare 2 driveshaft options
| Maker / product | Part # | Price | Fits / notes | Where | Status |
|---|---|---|---|---|---|
| PSI Conversion Adapter to mate a 1350 U-joint yoke to a 3-bolt differential Verified Our pick | (yoke adapter) | $54 2026-09-28 | Direct from PSI Conversion | ||
| Driveshaft shop (local) Engine-donor driveshaft cut to size and rebalanced Listed | — | 1988-1998 C1500/K1500 LS swaps Unconfirmed Confirm this We have not confirmed this part on this vehicle yet. If you installed it, tell us what you used and why. | donor truck + local shop | Used only |
Everything else1 note
- OBS 3-bolt differential flange may need a 1350 U-joint yoke adapter.
Why this step matters: 2 of 9 owner questions about this vehicle
- Best stall speed for a 97 K1500 5.7 with 4.56 gears?
- Setting up a half-ton OBS as a tow rig — what suspension/brake upgrades matter?
Ready for the next step when you've picked the transmission and how it's controlled, and know the crossmember, driveshaft and flexplate or bellhousing it needs.
Next: accessories & cooling →4Accessories & coolingOne accessory spacing, then cooling and A/C · 3 parts
Accessory drive
3 optionsWhy you need it: The balancer, water pump, brackets and pulleys must all be one spacing, or the belt won't line up. On 1988-95 trucks Kwik's R4 bracket reuses the stock compressor, but the old A/C hoses won't reach it in its new spot. More: accessory drive guide.
Our pick and alternatives3 options
Compare 3 accessory drive options
| Maker / product | Part # | Price | Fits / notes | Where | Status |
|---|---|---|---|---|---|
| Dirty Dingo LS R4 A/C Compressor Accessory Bracket Verified Our pick | DD-LS-R4-AC-TR | Direct from Dirty Dingo | |||
| Dirty Dingo LS Sanden A/C Compressor Accessory Bracket Verified | DD-SANDEN-AC-TR | Direct from Dirty Dingo | |||
| Kwik Performance R4 A/C bracket (reuse stock R4 compressor) Listed | K10623 | 1988-1995 OBS LS swaps for 1988–1995 only | Check price & fitment | In production |
Cooling
2 options · $480Why you need it: LS water pumps put both hoses on the passenger side and the engine needs a steam line, so the radiator needs LS-style ports or an adapter. A 4.3 radiator won't cool a 5.3: step up to the 5.7 tow-package unit (about 34 in) with LS1 F-body fans. More: radiator, fans and steam line.
Options2 options
We have not confirmed this part on this vehicle yet. If you installed it, tell us what you used and why.
We have not confirmed this part on this vehicle yet. If you installed it, tell us what you used and why.
Compare 2 cooling options
| Maker / product | Part # | Price | Fits / notes | Where | Status |
|---|---|---|---|---|---|
| GM (junkyard) 5.7L tow-package radiator (~34in) + LS1 F-body e-fans Community | — | 1988-1998 C1500 (5.3/6.0 + 4L80E) for 2WD only Unconfirmed Confirm this We have not confirmed this part on this vehicle yet. If you installed it, tell us what you used and why. | junkyard | Used only | |
| Radiator shop (local) Custom aluminum radiator + shroud + dual 14in fans Community | — | ~$480 2018 | Any (custom built to your truck) Unconfirmed Confirm this We have not confirmed this part on this vehicle yet. If you installed it, tell us what you used and why. | local radiator shop | DIY |
A/C
2 options · $250Why you need it: Where the compressor mounts (high or low) can decide frame, fender and header clearance, so pick it before you buy brackets. Dirty Dingo makes both R4 and Sanden compressor brackets for OBS swaps; a relocated R4 needs custom A/C lines and an oil pressure sensor adapter. More: accessory drive guide.
Options2 options
We have not confirmed this part on this vehicle yet. If you installed it, tell us what you used and why.
Compare 2 A/C options
| Maker / product | Part # | Price | Fits / notes | Where | Status |
|---|---|---|---|---|---|
| Aftermarket R4 A/C compressor bracket Community | — | 1988-1998 OBS 5.3 swap Unconfirmed Confirm this We have not confirmed this part on this vehicle yet. If you installed it, tell us what you used and why. | Amazon (per 95 OBS build) | In production | |
| Dirty Dingo A/C compressor bracket Listed | — | $250 2026 (AZ Pro build) | 1988-1998 GM truck LS swap | Direct from Dirty Dingo | In production |
More: Accessory drive guide · Cooling guide
Ready for the next step when you've picked one accessory spacing, with the balancer, water pump and brackets to match.
Next: exhaust →5ExhaustHeaders or manifolds that clear where the engine sits · 1 part
Headers & exhaust
4 options · $1–$684.96Why you need it: Headers are shaped around one chassis's frame, steering and floor, so they have to be made for your vehicle and engine position. 2WD long tubes don't fit 4WD trucks (K1500 uses 25-1011 or 25-1077), and the X-pipe needs a modified crossmember. Cast manifolds are the easy 4WD fit. More: headers and exhaust by chassis.
Options3 of 4
We have not confirmed this part on this vehicle yet. If you installed it, tell us what you used and why.
Compare 4 header & exhaust options
| Maker / product | Part # | Price | Fits / notes | Where | Status |
|---|---|---|---|---|---|
| ICT Billet LS Headers 88-98 2wd OBS 78-87 G-Body Listed 2WD | SPE-25-1137 | $380 2026-09-29 | for 2WD only Unconfirmed Confirm this We have not confirmed this part on this vehicle yet. If you installed it, tell us what you used and why. | Direct from ICT Billet | Out of stock |
| Speed Engineering OBS LS swap kit header options (shorty / mid-length / longtube) Listed 2WD | — | mid-length 1-3/4 +$60.00; longtube 1-7/8 2WD +$150.00 2026-10-01 | 1988-1998 C1500 2WD for 2WD only | Direct from Speed Engineering | In production |
| Hooker BlackHeart LS swap cast exhaust manifolds Listed | 8502HKR | $675.95 2026-10-01 | 1988-1998 C1500/K1500 (OBS) LS swap; tight-tuck design intended for most popular chassis | Buy | In production |
| Speed Engineering 1-7/8 in stainless longtube headers + 3 in off-road X-pipe kit Listed 2WD | 25-1137 | $684.96 2026-10-01 | 1988-1998 C1500 2WD (GMT400 OBS); 4.8/5.3/6.0/6.2/LS1/LS2/LS3/LS6/LSA Doesn't fit: 4WD - will not fit 4WD trucks (K1500 use 25-1011 or 25-1077) for 2WD only | Check price & fitment | In production |
More: Headers & exhaust guide
Ready for the next step when you've picked headers or manifolds that clear where your mounts put the engine.
Next: fuel system →6Fuel systemPump, lines and pressure for the LS · 1 part
Fuel system
3 options · $30Why you need it: An LS runs about 58 psi of fuel pressure; a carbureted system runs 5–7 psi. 1988-95 TBI trucks ran a low-pressure pump: fit an in-tank EP381 and replace every soft fuel hose. 1996-98 trucks keep the stock pump. More: fuel system & E85 guide.
Options3 options
We have not confirmed this part on this vehicle yet. If you installed it, tell us what you used and why.
Compare 3 fuel system options
| Maker / product | Part # | Price | Fits / notes | Where | Status |
|---|---|---|---|---|---|
| WIX Corvette fuel filter/regulator Listed | 33737 | 1988-1998 OBS (mounted in factory filter location) | Buy | In production | |
| HotRodan (AN fittings) M16/M14 to AN-6 sender adapter fittings Listed | — | 1988-1998 GMT400 (return-less or return-style AN-6 PTFE layouts) | Direct from HotRodan (AN fittings) | In production | |
| AC Delco EP381 in-tank fuel pump upgrade Listed | EP381 | ~$30 2026 (AZ Pro build) | 1988-1995 TBI trucks (drop-in on factory assembly) for 1988–1995 only Unconfirmed Confirm this We have not confirmed this part on this vehicle yet. If you installed it, tell us what you used and why. | parts stores | In production |
More: Fuel & E85 guide
Ready for the next step when you've decided return or returnless, and sized the pump and injectors for your power and fuel.
Next: wiring, computer & tune →7Wiring, computer & tuneHarness, computer and tune matched to the engine · 1 part
Harness & computer
3 options · $150–$1,099Why you need it: The computer and harness have to match the engine's crank signal (24x or 58x) and throttle (cable or drive-by-wire), and the tune has to turn VATS off. More: 24x vs 58x, and which harness.
Our pick and alternatives3 options
We have not confirmed this part on this vehicle yet. If you installed it, tell us what you used and why.
We have not confirmed this part on this vehicle yet. If you installed it, tell us what you used and why.
Compare 3 harness & computer options
| Maker / product | Part # | Price | Fits / notes | Where | Status |
|---|---|---|---|---|---|
| PSI Conversion 99–07 Gen 3 LS/Vortec (24X) Engine Controller Kit, drive-by-cable, w/ 4L60E-75/4L80E control (standalone harness, MAF, flashed ECM, bracket) Verified Our pick | (Gen 3 24X DBC kit) | $1,099 2026-09-28 | Ready-to-run option; flashed for application | Direct from PSI Conversion | |
| Holley Terminator X (universal LS ECU kit) Community | — | 1988-1998 C1500/K1500 LS swaps Unconfirmed Confirm this We have not confirmed this part on this vehicle yet. If you installed it, tell us what you used and why. | Holley / retailers | In production | |
| DIY Stock harness rework + PCM reprogram Community | — | ~$150 harness mods + $75 PCM reprogram 2026 (Laurenceville Garage) | 1988-1998 OBS LS swaps Unconfirmed Confirm this We have not confirmed this part on this vehicle yet. If you installed it, tell us what you used and why. | local tuner / DIY | DIY |
New Already have a tune in it? Send us the file for a free Tune Report: what to fix first, in plain English, within 1 business day. See what you get →
Why this step matters: 1 of 9 owner questions about this vehicle
- I have a 2004 Yukon Denali donor for a 1995 Sierra roller - what do I need, and can I go drive-by-cable?
More: ECU comparison · Tuning
Ready for the next step when the harness and computer match your engine's crank signal and throttle, and you have a plan for the tune.
Next: cost →8CostThe whole budget, not just the engine
We don't have notes for this step on this vehicle yet, so measure and confirm with the part maker before you buy.
Answered for this vehicle1 answer
That's the last step. Put your picks together in the planner.
Plan your exact combination →Swap kits sold for this vehicle
Why it matters: the kit's mounts decide where the engine sits, and that decides oil pan, header and crossmember clearance. Confirm the kit lists your exact years. More: engine mounts and swap kits.
- — Amazon (3rd-party)
- — PSI Conversion
Questions about this swap
Every LS swap also needs
An oil pan that clears
Compare GM LS pans by sump position and depth.
Accessory drive spacing
F-body, car, truck and Corvette offsets.
Fuel system sizing
Injector and pump sizing for your power goal.
A harness, computer and tune
VATS delete, 24x vs 58x, drive-by-wire, harness makers.
A transmission
4L60E to 8HP70 behind an LS.