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Official 3800 NA to Supercharged Top Swap Support & Build Thread
This is the official community discussion and support thread for the W-BodyTech 3800 NA to Supercharged Top Swap Guide.
The main guide covers both:
• Series II: L36 → L67 top swap
• Series III: L26 → L32 top swap
It includes parts and part numbers, Series II vs. Series III differences, torque specifications, removal and installation procedures, fuel-system information, supercharger drive components, wiring considerations, tuning requirements, and first-start checks.
This thread is where we can go beyond the guide and build a larger knowledge base from actual swaps.
Before Starting Your Swap
Read through the complete guide first:
3800 NA to Supercharged Top Swap Guide
Pay particular attention to whether you're working with an L36/L67 Series II combination or an L26/L32 Series III combination. Many components are shared, but the heads, intake/supercharger configuration, fuel system, throttle body, sensors, wiring, and PCM strategy can differ.
Need Help? Include This Information
If you're troubleshooting a swap, please include as much of the following as possible:
Vehicle: Year / Make / Model
Original Engine: L36 / L26 / Other
Top Swap: L67 Gen 3 / L32 Gen 5 / Mixed
PCM: Stock / Tuned / PCM swap
Injectors: Type or part number
Supercharger Pulley: Size
Fuel System: Return / Returnless / Modified
Transmission: Model and modifications
Current Mods: Exhaust, cam, rockers, intercooler, etc.
Problem: Describe exactly what the vehicle is doing
Codes: Include all current DTCs
Scan Data: Include KR, AFR/fuel trims, boost and other relevant data when available
Photos, screenshots, logs, part numbers and wiring information are strongly encouraged.
The more information you provide, the easier it is for the community to help diagnose the problem.
Share Your Completed Top Swap
If you've completed a swap, post your setup.
We're especially interested in documenting:
• Vehicle and model year
• L36 → L67 or L26 → L32
• Gen 3 or Gen 5 M90
• Parts used
• Part numbers you verified
• Injector setup
• Pulley size
• PCM/tuning setup
• Transmission setup
• Supporting modifications
• Problems encountered
• Solutions that worked
• Photos of the build
• Scan data or results
Real-world combinations are extremely valuable because there are many different ways these swaps have been completed over the years.
Help Us Improve the Guide
The W-BodyTech guide is intended to remain a living technical resource.
If you find:
• An incorrect part number
• A superseded GM part number
• A missing torque specification
• A year-specific difference
• A Series II vs. Series III difference
• A wiring or sensor difference
• A better installation procedure
• An important compatibility issue
• A useful photo or diagram
Post it here with the source or details whenever possible.
Verified information from this thread may be incorporated into future revisions of the main guide so the information doesn't get buried in years of forum posts.
Tuning & First-Start Questions
A proper PCM calibration is required for a supercharged conversion.
Do not assume that installing the hardware alone makes the vehicle safe to drive under boost.
For tuning-specific discussions, visit:
W-BodyTech PCM Tuning Forum
For troubleshooting, include scan data whenever possible. Knock retard, fuel trims, commanded fueling, boost and other data can provide considerably more information than trying to diagnose a problem from symptoms alone.
Keep the 3800 Knowledge Alive
A lot of the original 3800 information from old forums, personal websites and build threads has disappeared over the years. One of the goals of W-BodyTech is to preserve that information while continuing to document what the community learns today.
If you've done one of these swaps, even if it was years ago, your experience can help the next person doing it.
Post your builds, questions, corrections, part numbers, photos and lessons learned below.
→ Read the Complete 3800 NA to Supercharged Top Swap Guide