Four TBI – 140 Engine Stagged Injection – Special Order

4 TBI kits production have limited production and you must have the patience and skills to make it work.  Once it is setup, what a kick in the pants to drive. 

4 TBI Kit is $2199.00

This kit is NOT recommended for the novice as 4 throttle bodies are a lot more complicated than two to obtain that perfect running engine.  You will also need a working 4-carb linkage as the secondary TBI openings need to be precise.  For those wanting the power of a 140 HP engine, but the simplicity of EFI, I would suggest using the bored 2 TBI version with block-off plates or Fake TBIs on the secondaries.

Lets Talk Performance:

The Corvair 140 HP 4 TBI setup is not about fuel economy….it’s about power.   Our Throttle bodies are bored,  have new throttle shafts, and have the venturi removed to provide maximum airflow, fuel delivery, and power.  We did not design this system for racing, but if you want a good pull with plenty of top-end… this is your system.  We program the ECMs for the middle-of-the-road engine setups, but this kit will require a laptop to tune your engine further.  A Wideband O2 sensor is required for tuning and precise fuel control of these engines. The Progressive linkage system along with the staged injection system uses the primary throttle bodies for idle and light throttle.  As the throttle increases, the secondary throttle bodies begin to open and those injectors start. Using staged injection will avoid stutter at “tip-in” and better fuel mileage as it only uses the secondaries when under medium or full throttle. If you are interested in more power than a conventional setup but want decent driving around mileage,  you may want to consider the Dual TBI kit with block-off plates or install “thin plates” under the secondaries of the 4x kit to keep the quad look.  This kit will require a working Corvair 4 TBI factory progressive linkage that will open the secondaries at approx 35% for proper operation.

Staged Injection:  This is similar to the progressive carbureted system that GM used on the Corvair 140 engine.  The primary throttle bodies are in use until the throttle is pressed past 35% of the Throttle (as indicated by TPS).  At 35%, The secondary will start to open and fuel will begin to be injected into the secondary as well as the primaries.  The primary and secondary’s will inject fuel as indicated in the fuel tables and can be adjusted for maximum power.  You will need one (1) wideband O2 sensor mounted on the passenger-side dual exhaust. 

Ignition: The standard kit has the Crank Wheel trigger system, GM LSX ignition module, and your standard coil.  This configuration is simple and supplies ample spark, but for those who want a little more spark, we recommend the “Flame Thrower 40011 40k” coil.  These upgraded coils provide more than enough spark for Corvair engines except for extreme setups.   Using this type of setup, you can create custom ignition curves and factor in things like temp. The 6025 EFI Distributor replaces the crank wheel system and is available for an additional cost.  If you use the crank wheel system, we do not recommend the Spartan2 system.

Fuel System:  The engine bay fuel lines are not included in the kit, but test lines and fittings may be included in your kit at no cost to build your own.  The kit does include a Fuel pressure regulator and a fuel pulse dampener that is installed between the engine and body fuel line.   The fuel pulse damper will lessen line pulses which can cause uneven fueling.

O2 Sensor: You will need to purchase one (1) WBO2 controller and sensor of your choice.  The 4 TBI Wiring harness is prewired for one (1) WBO2 sensor and is mounted on the driver’s side dual exhaust.  The Staged injection system can only support one (1) O2 sensor.

The 4-Throttle body Injection system can also be used on engines that have had the extra Carburetor pad added (Fitch type).  The Throttle body injection unit uses the standard Corvair gaskets but will need insulators to ensure the proper height of the TBI. Ignition.



The kit includes all items from the fuel pressure regulator to the engine. The fuel pump is NOT included in the kit but is available at an additional cost.

Kit Contents

1 ea      Throttle body assembly w/Injector and TPS
1 ea      Throttle body assembly w/Injector, ICS and ICS Solenoid
2 ea     Throttle body assembly, Secondary
1 ea      Fuel Line Passenger Side ¼”
1 ea      Fuel Line Drivers Side ¼”
1 ea      Fuel Line Main 5/16”
1 ea      Fuel Line “T” to Tunnel Line 5/16”
1 ea      Fuel Line Pressure Gauge 5/16”
1 ea      Fuel Pressure Regulator/Filter, 58 lbs with 5/16″ hose barb
1 ea      Fuel Pressure Regulator to Fuel Line adapter (3/8″ x 5/16″)
1 ea      Fuel Pressure Regulator to Fuel Line adapter (5/16″ x 5/16″)
1 ea      Fuel Return Line Adapter (5/16”) w/Clamps
1 ea      Control Panel with screws
1 ea      2 TBI Wiring Harness with Relays
1 ea      ECU-S Computer  (programmed and user adjustable)
1 ea      Map Sensor, GM Type (Mounted to Control Panel)
1 ea      Head/Engine Temp Sensor (3/8-16 thread)
1 ea      Fuel pump block-off with O-Ring
1 ea      Late Model GM Ignition Module w/Bracket
1 ea      36-1 Trigger Wheel w/bolts and spacers
1 ea      Crank Sensor Bracket
1 ea      Crank Sensor
1 ea      Diode to prevent alternator feedback
1 ea      USB to 2.5mm ECM to Laptop Cable
2 ea    **Carburetor base core required
1 ea    **Distributor core required

Cores:   **Send your cores (Early models are preferred) when you order to allow time for the modifications to these items and avoid delays.  Your cores must be in reasonably good shape and must have a fairly straight Bell Crank, a throttle plate, and a throttle shaft that is not binding.  Unusable bases have to be thrown away, waste your shipping, and another set of cores will be needed.  A core charge will be charged for each unusable core.