From the late-1950s through the mid-1960s, GM offered
the Ram Jet fuel injection system in a variety of models.
Today, the Ram Jet name is back as a great-looking,
great-performing factory-fuel-injected crate engine!
The Ram Jet 350 evokes the nostalgic look of the early
fuel injection system, with a styled intake plenum—but
that’s where the similarities end. Instead of a mechanical
injection system, the Ram Jet 350 is fed by a state-of-theart,
electronically controlled port fuel injection system.
Developed by GM to the same standards as productionvehicle
systems, the Ram Jet 350 delivers exceptional
throttle response and performance—all enabled by the
sophisticated, latest-generation MEFI 4 controller, which
has improved electronics and closed loop capability
(compared with the previous MEFI 3 system) for great
all-around drivability.
A tried-and-true 350-cubic-inch small-block combination
anchors the Ram Jet 350. It is designed for long-lasting
durability and pump-gas compatibility, with iron Vortec
cylinder heads, a hydraulic roller camshaft and 9.4:1
compression.
GMPP delivers the engine with the necessary wiring
harness and detailed instructions. It can be installed on
any 1979-or-earlier vehicle originally equipped with a
carburetor. So, quit "fuelin’" around with carbs and give
your vintage ride a modern injection of performance!

• TECH SPECS: Ram Jet 350
• Part Number: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12499120
• Engine type: . . . . . . . . . . . . . . . . . . . . . . . Chevy small-block V-8
• Displacement (cu in): . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 350
• Bore x stroke (in) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.00 x 3.48
• Block: . . . . . . . . . . . . . . . . . . . . cast iron with 2-bolt main caps
• Crankshaft: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . cast iron
• Connecting rods: . . . . . . . . . . . . . . . . . . . powdered metal steel
• Pistons: . . . . . . . . . . . . high-silicon aluminum with offset pins
• Camshaft type: . . . . . . . . . . . . . . . . . . . . . . . . . . hydraulic roller
• Camshaft lift (in): . . . . . . . . . . . . . . . . .431 intake / .451 exhaust
• Camshaft duration (@.050 in) . . . . . 196° intake / 206° exhaust
• Cylinder heads: . . . . . . . . . . . . . . . . . . . . . . iron; 64cc chambers
• Valve size (in): . . . . . . . . . . . . . . . . . . 1.94 intake / 1.50 exhaust
• Compression ratio: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.4:1
• Rocker arms: . . . . . . . . . . . . . . . . . . . . . . . .aluminum roller style
• Rocker arm ratio: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5:1
• Recommended fuel: . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 octane
• Ignition timing: . . . . . . . . . . . . . . . . 10 degrees BTDC @ 700 rpm
• Maximum rpm: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5500

INSTALLATION NOTES
• Requires addition of externally balanced flexplate for automatic
transmission or externally balanced flywheel for manual transmission.
See chart on page 80.
• Installer to supply 12-volt power source and fuel.
• See instructions for fuel pump recommendation.
• Intended for 1979-and-earlier pre-emissions street vehicles or
all off-road vehicles.
• Not intended for marine use.
• IMPORTANT! MEFI 4 computer has a "green" mode that controls
rpm during the break-in period; from start-up to the end of the
first hour is 4000 rpm, the second hour is 4500 rpm and the
third hour is 5500 rpm.