4bbl Carbureted Off-Road LPG Parts Package

Applications

• Pre-1987 Domestic Engines with 4bbl carburetors
• Stock small block and big block V8 engines
• Modified six cylinder engines (higher lift / longer duration cam, free flowing exhaust, etc.)
• Large vehicles such a pickup trucks
• Off-road use only

Venturi Mixer

• "Carb Hat" adapter to suit carburetors with 5-1/8" air horn
• Adapter is 3.5" high - measure for sufficient clearance before ordering!
• 3" OD Single venturi inlet standard
• Single fuel inlet

General Information

• Ignition timing should be optimized for propane operation
• Compression can be increased to take advantage of propane's 104 octane rating
• Components in package may differ from those shown in pictures
• Recommended for applications up to 350 hp
• Provides better fuel economy than Impco dual fuel systems.
• This package was created by Raso Enterprises from Technocarb components.
• Based on Technocarb's mono-fuel off-road carburetor kit.
• As a PARTS PACKAGE, this item carries NO WARRANTY.

Components Included in Kit

• EFS-600 LPG Fuel Controller
• TC 210 Scan Tool (used to calibrate the EFS-600)
• Bosch 4-wire heated Oxygen Sensor
• High Flow LPG Vaporizer
• Carburetor adapter
• Single Venturi Mixer (3" or 3-1/2" OD Bonnet)
• LPG Fuel lock-off with internal filter
• Gasoline fuel lock-off
• Fuel Safety Switch
• Remote LPG Level Indicator
• Installation Instructions

Parts package substitutes above mixer for 4bbl carburetor shown below. 

Components NOT Included in Kit

• Fuel tank
• Fuel line from tank to fuel lockoff valve
• Remote fill valve (if required)
• Air cleaner assembly
• Use Remote air cleaner assembly from suitable donor vehicle
• Or Baldwin air filter housing PN HSG3060 for 3" bonnet or PN HSG3046 for 3-1/2" bonnet.
• LPG-OFF-Gasoline operation toggle switch
• Fuel Gauge
• Use GM 0-90 ohm fuel gauge
• Or connect to vehicle fuel gauge through toggle switch

System Operation

• Vehicle runs on gasoline exactly the same as with unmodified vehicle
• To switch-over to LPG, the carburetor must first be emptied of gasoline.  This requires you toggle the switch to OFF position where both fuels are shut off to the engine.  This is best done while stopped in a safe location.
• When engine begins to stumble from lack of gasoline in the fuel bowl, toggle the switch to the LPG position.  When the engine begins to idle smoothly, it is safe to begin driving while running on LPG.
• It is best not to run out of either fuel but if you run out of LPG, you must stop the vehicle in a safe location, toggle back to the gasoline position and crank the engine (assuming you have a mechanical fuel pump) until the engine starts.  If you have an electric fuel pump, you may instead let the pump run for a minute to refill the carburetor before restarting.

Ignition Timing

• For best fuel LPG economy, the engine's timing advance curve should be optimized for LPG.  While not optimal for gasoline operation, you should only be running on gasoline long enough to keep the fuel from becoming stale.
• Many vehicles do not have readily available timing re-curve kits any more.  You may want to consider converting to a fully programmable dual map ignition system such those available from Autosport Labs.

SPECIFY BONNET SIZE (3" or 3-1/2" OD) TO SUIT AIR CLEANER HOSE WHEN ORDERING!  BE SURE YOUR AIR CLEANER IS SIZED FOR YOUR ENGINE.