12499121 RamJet 502 Crate Engine PFI with Aluminum Heads

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Item #: 12499121
Reg. Price: $15,223.09
Our Price: $12,400.24


12499121 Ramjet 502
Outrageous style and fuel-injecteddrivability – all with big-block power!

The Ram Jet 502 blends the legendary torque and performance of theBig-Block with a modern port fuel injection system and tunnel ram-style high-rise intake manifold. It’s a combination that offers uncompromising performance in a visually stunning presentation.
The unique Ram Jet fuel injection system stands 11 inches tall at itshighest point and consists of a two-piece manifold/plenum assembly,eight injectors, a throttle body, and an updated MEFI 4 controller.

Setup instructions are included, making it a simple, “plug-and-play” installation.
Supporting the unique induction system is a robust bottom end withan all-forged rotating assembly and a smooth hydraulic roller camshaft.
The heads are GMPP’s high-fl ow aluminum oval-port parts.

You’ll need to check your ride for clearance before closing the hood over the Ram Jet 502. Then again, it looks so impressive, you may just want to cruise around with the hood off!

The Ram Jet manifold stands eleven inches tall as measured from the front and rear "china wall" on the cylinder block. That''s just half an inch taller than a typical single plane high rise manifold, Holley carb and air cleaner combo.

Equipped oil pan may not clear Chevelle and Camaro applications.

• The Ram Jet 502 requires a 12-volt power source(and ground), coolant, exhaust system, fuel feedand fuel return line (to the fuel tank). An in-tankfuel pump is recommended
• Clutch linkage bosses are now drilled and tapped.
When using cast-iron exhaust manifolds, lowerhead bolts may need to be replaced with boltswith shorter heads, for clearance
• Designed for pre-1976 street vehicles or anyoff-road vehicle
• Not intended for marine applications
• IMPORTANT! For a safe, proper and troublefreeengine break-in, the MEFI 4 computer hasa “green” mode that controls rpm during thebreak-in period. During this period, engine speed islimited to 4,000 rpm in the fi rst hour, 4,500 rpm inthe second hour and 5,500 rpm in the third hour
• Comes with a automatic flexplate

For 1978 or older vehicles.
Service Parts Listing

Have an older Ramjet 502 with an MEFI3? Update it with the new MEFI 4 Module/Harness kit #12499117: click here

ZZ 502/502 Technical Information

Part Number: 12499121
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: 92 octane
Ignition Timing: Base 8° BTDC, 30° Total
Maximum Recommended rpm: 5,800
Balanced: External

Technical Notes:

Distributor P/N 1104067 or melonized distributor gearP/N 10456413 must be used on all crate engines with steel camshafts.
• The clutch linkage boss is cast in this block, but it is not drilled or tapped.
• When using cast iron exhaust manifolds the lower head bolt may need to be replaced with bolt with shorter heads.

Service Parts Listing

Terms and Conditions
Warranty Information
GM Performance Crate Engine Start-up Instructions

Click here to download Product Information Sheet 


This engine is eligible for a $500 rebate when you also purchase:


19329795 T56 Manual Transmission and
19329901 Transmission Installation Kit


Click here for Rebate Information



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