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Chevrolet Performance Ram Jet 502 Crate Engine

Brand: Chevrolet Performance

Part Number: 12499121


The product's part number has been discontinued.


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  • 502 hp @ 5,300 rpm/568 lb.-ft. @ 3,600 rpm
  • MEFI 4 Controlled Port Fuel Injection
  • Plug-and-play Setup Includes Instructions
  • Aluminum Oval Port Heads & Hyd. Roller Cam


Ram Jet 502 Crate Engine

12499121 Chevrolet Engine

502 hp @ 5,300 rpm / 568 lb.-ft. @ 3,600 rpm


Make a Statement When You Open Your Hood!

The Chevrolet Performance Ram Jet 502 crate engine blends the legendary torque and performance of a Big-Block Chevy with modern port fuel injection and a tunnel ram-style high-rise intake manifold. It is a combination that offers uncompromising performance - including 502 hp and 568 lb.-ft. of torque - in a visually stunning presentation!

The unique GM Ram Jet fuel injection system stands 11 inches tall at its highest point and consists of a two-piece manifold/plenum assembly, eight injectors, a throttle body, and an updated MEFI 4 controller. A robust bottom end featuring an all-forged rotating assembly is installed in a strong, latest-generation block casting with four-bolt main caps. It also has high-flow aluminum oval-port cylinder heads, and includes an aluminum short style water pump and HEI distributor.

Ram Jet 502 Crate Engine

P/N 12499121

Ram Jet 502 Tech Specs:
Engine Type: Chevy Big Block V-8
Displacement (cu in): 502
Bore x Stroke (in): 4.470 x 4.000
Block (P/N 19170540): Cast-iron with 4-bolt main caps
Crankshaft (P/N 10183723): Forged steel
Connecting Rods (P/N 19170198): 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° intake / 234° exhaust
Cylinder Heads (P/N 12363390): Aluminum oval port; 110cc chambers
Valve Size (in): 2.250 intake / 1.880 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 19168602): Aluminum, short-style
Flexplate (P/N 10185034): 14"
Recommended Fuel: Premium Pump
Ignition Timing: 35° Total at 4,000 rpm
Maximum Recommended rpm: 5,800
Balanced: External


Recommended Transmission:  SuperMatic™ 4L85-E Four-Speed Automatic P/N 19300175


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 bosses are now drilled and tapped. When using cast-iron exhaust manifolds, lower head bolts may need to be replaced with bolts with shorter heads, for clearance
• Designed for pre-1976 street vehicles or any off road vehicle
• Not intended for marine applications
• 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. During this period, engine speed is limited to 4,000 rpm in the first hour, 4,500 rpm in the second hour and 5,500 rpm in the third hour.

Note: Distributor with melonized steel gear MUST be used with long-blocks and Partial engines with steel camshafts, or engine damage will occur.

Chevrolet Performance Crate Engines include a 24-month or 50,000-mile (80,000 kilometer) limited warranty.

Click here for more detailed warranty information.

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