Chevy Ram Jet 502

The fuel injected 502 big block from GM Performance is a sweet engine! The 11 inch manifold provides great throttle response. Combine that instant punch with 502 horsepower and 565 lb-ft of torque and you have yourself a fire breathing EFI monster!

The Ram Jet 502 is the perfect engine to fill up a large engine bay. The intake manifold really stands tall and looks great in classic trucks and other massive engine spaces. Most high rise intakes are just slightly shorter than this fuel injection manifold - it will fit in most of the same spaces that any high rise intake was installed.

Featuring a 4.00" forged crankshaft, 4.47" forged aluminum pistons, forged rods and a roller camshaft, the Ram Jet 502 is both reliable and a strong runner. The aluminum heads are an oval-port intake design. They utilize 2.25" intake and 1.88" exhaust valves. These heads are very efficient and flow well. Hood clearance at the throttle body should be checked for interference.

Possible Applications

  • Build a fuel-injected car
  • Build a high tech EFI car
  • Modernize 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

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.