Cummins Engine Swap Kits

CMW Trucks - 1947 - 1972 Chevy Truck Parts


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Ram Jet 502

With an 11" fuel-injected intake manifold flexing out of the top of a 502" big-inch Rat, the GMPP Ram Jet 502 is just plain cool. Not only attractive, the Ram Jet intake adds a significant amount of function to the big-block with amazing throttle response that you just have to experience to believe. Combining our aluminum-headed 502 with a modern fuel-injected intake results in 502 horsepower and 565 lb.-ft. of neck-snapping torque. With the Ram Jet intake, you also have over 500 lb.-ft. of torque available from 2200 rpm on up.

Without question, that big, fuel injection intake stands out the most on the Ram Jet 502. Functional as it is attractive, the Ram Jet intake system enhances the already impressive torque band of the 502. The intake gobbles up air and stuffs it into the awaiting cylinders with incredible efficiency. The impressive intake only sits a half-inch taller than a comparable carbureted system with a high-rise intake manifold, Holley four-barrel carb and air cleaner.

The Ram Jet 502 features a 4.00" forged crankshaft, 4.47" forged aluminum pistons, forged rods, and a roller camshaft. The aluminum heads are our highly efficient oval-port intake design, and they utilize 2.25" intake and 1.88" exhaust valves. Underhood clearance at the throttle body should be checked for interference.

Possible Applications

  • Build a fuel-injected ‘55-57 shoebox
  • Go high tech with your ‘32 hot rod
  • Restification for a show car

*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: 12499121
Engine type: Chevy big-block V-8
Displacement (cu in): 502
Bore x stroke (in): 4.47 x 4.00
Block (P/N 10237292): Cast iron with 4-bolt main caps
Crankshaft (P/N 10183723): Forged steel
Connecting rods (P/N 10198922): Forged steel, shot peened
Pistons (P/N 12533507): Forged aluminum
Camshaft type (P/N 12366543): Hydraulic roller
Camshaft lift (in): .527 intake / .544 exhaust
Camshaft duration (@.050 in): 224'c1 intake / 234'c1 exhaust
Cylinder heads (P/N 12363390): Aluminum oval port; 110cc chambers
Valve size (in): 2.25 intake / 1.88 exhaust; stainless steel
Compression ratio: 9.6:1
Rocker Arms (P/N 12368082): Stamped steel
Rocker arm ratio: 1.7:1
Distributor (P/N 1104060): HEI type
Throttle body (P/N 17113524): Included
Water pump (P/N 14058915): Aluminum, short-style
Spark plugs & wires: Included
Starter (P/N 9000852): Included
Flexplate (P/N 10185034): 14"
Recommended fuel: 92 octane
Ignition timing: 8'c1 BTDC @ 800 rpm; 36'c1 total @ 5000 rpm
Maximum rpm: 5800

Chevy Performance ram jet 502 engine image

Part #: 12499121

ram jet 502 dyno image

Installation Notes

  • The Ram Jet 502 requires a 12-volt power source (and ground), coolant, exhaust system, fuel feed and fuel return line (to the fuel tank). An in-tank fuel pump is recommended.
  • Clutch linkage boss is cast into block, but must be drilled and tapped. When using cast iron exhaust manifolds, lower head bolts may need to be replaced with bolts with shorter heads, for clearance.
  • 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.