Cummins Engine Swap Kits

CMW Trucks - 1947 - 1972 Chevy Truck Parts


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Ram Jet 350 - Port fuel injection meets a small-block classic.

Restification—blending the best of the old with the best of the new is the hottest trend in hot rodding today. GM Performance Parts has just what you need to put a modern twist on your favorite classic hot rod with our amazing Ram Jet 350 crate engine. GM offered the Ram Jet fuel injection system on a variety of models in the late-1950s through the mid-1960s, but the Ram Jet has never looked as good as it does in the Ram Jet 350 crate engine.

The Ram Jet 350 has a styled intake plenum that feeds a state-of-the-art, electronically controlled port fuel injection system. Developed by GM to the same standards as production vehicle systems, the Ram Jet 350 delivers exceptional throttle response and performance. This is made possible 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 venerable 350 cubic inch small-block combination anchors the Ram Jet 350. It is designed for long-lasting durability and pump-gas compatibility, with Vortec cylinder heads, a hydraulic roller camshaft and 9.4:1 compression.

GM Performance Parts delivers the engine with the necessary wiring harness and detailed instructions. It can be installed on any 1976-or-earlier vehicle originally equipped with a carburetor.

Possible Applications

  • Update the Stingray
  • Round out any hot rod that needs a little “something” under the hood
  • Use it to start a conversation on Friday night

*Applications have not been validated. They are merely suggestions of how you might enjoy your GM Performance Parts crate engine. Some applications may affect engine warranty. See specific warranty information. Some applications may not be emission legal; check state and local ordinances.

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 (P/N 10243068): Cast iron
Connecting rods (P/N 10108688):Powdered metal steel
Pistons (P/N 88894280): Hypereutectic aluminum
Camshaft type: Hydraulic roller
Camshaft lift (in) (P/N 14097395): .431 intake / .451 exhaust
Camshaft duration (@.050 in): 196'c1 intake / 206'c1 exhaust
Cylinder heads (P/N 12558060): Vortec iron; 64cc chambers
Valve size (in): 1.94 intake / 1.50 exhaust
Compression ratio: 9.4:1
Rocker Arms (P/N 12367346): Aluminum roller style
Rocker arm ratio: 1.6:1
Recommended fuel: 92 octane
Ignition timing: 10 degrees BTDC @ 700 rpm
Maximum rpm: 5500

Chevy Performance Ram Jet 350 Engine Image

Part #: 12499120

ram jet 350 dyno image

Installation Notes

  • NOTE: Distributor with melonized steel gear MUST be used with long blocks and partial engines with steel camshafts, or engine damage will occur.Wash Your Hands First
  • Comes with externally balanced, manual transmission flywheel; change
    to externally balanced flexplate for automatic transmission applications.
    See chart on page 171.
  • Installer to supply 12-volt power source and fuel.
  • See instructions for fuel pump recommendation.
  • Intended for pre-1977 street vehicles or all off-road vehicles.
  • Not intended for marine use.
  • IMPORTANT! For a safe, proper and trouble-free engine break-in, the 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.