Converting from a carburetor to Throttle Body Injection (TBI) on your 73–87 C10’s 350 is a popular mod – it improves cold starts, fuel economy, and driveability, especially at altitude. Here’s a complete guide.
Why TBI Over a Carb?
- Better cold start performance (no choke adjustment)
- More consistent fuel delivery at altitude
- Improved throttle response
- Slightly better fuel economy
- Can still use a stock-style air cleaner
The TBI System:
The 1987–1995 GM TBI (Throttle Body Injection) system uses two injectors on top of the intake manifold, an ECM (computer), and various sensors to control fuel delivery. It operates at lower pressure than multiport EFI (10–13 PSI vs 58+ PSI).
Key Components:
- TBI unit (throttle body with injectors)
- ECM/PCM
- In-tank or inline fuel pump (TBI-rated, 10–15 PSI)
- Fuel pressure regulator (integral to TBI unit)
- Intake manifold (must accept TBI throttle body)
TBI-Compatible Intake Manifold:
Edelbrock 3704 Performer TBI Intake Manifold for SBC 350 – Designed specifically for TBI throttle body mounting with the correct bolt pattern and coolant crossover passages.
Sourcing the TBI Parts:
The cheapest way is to buy a complete TBI donor truck from a 1987–1992 C/K truck. You get the ECM, TBI unit, sensors, and harness all matched together.
Fuel System Modifications:
- Replace the mechanical fuel pump with an electric pump
- Add a fuel filter rated for EFI
- Seal the original fuel sending unit return port if converting to returnless
Is It Worth It?
For a daily driver or weekend truck, yes – the TBI conversion is absolutely worth it for driveability. For a show truck, a properly jetted carb is simpler. For an off-road truck, TBI is great for starting at odd angles.
The Alternative: Skip TBI and Go Full LS
Many C10 owners skip TBI entirely and go straight to an LS swap. It costs more initially but gets you modern performance and fuel injection in one go.
Have you done a TBI swap on your C10? Was it worth it? Share your experience!