12499121 - Chevrolet Performance Parts Ram Jet 502 502CID 502HP Crate Engine

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Now with NEW MEFI 4 Controller with O2 Sensor!

The recipe is simple; one part attitude, one part driving perfection, one part leading factory technology, and five hundred and two parts hungry rat motor.

Ram Jet 502, you either have one or you want one! When the idea of an all new big-block fuel injection system first came up, we all thought it was a good one. When it was proposed that it be integrated with our 502 crate engine, we thought somebody clearly lost their mind. Who could possibly need the awesome, flat, broad torque curve only available with a long runner dry manifold? And who would want the neck-snapping throttle response of MEFI 4 controlled port fuel injectors? And what would be the need for aggressive tunnel ram styling? But then we remembered we're not building 100 mile per gallon, 0 to 60 in a week, econo-scooters. We're in the hot rod business! So we called together engine management system experts from GM Powertrain, our own GMPP engineers, and fuel injected race engine builder and GMPP Pro Mod racer Harold Martin.

After some great discussions, a little debate, a lot of late nights and 50 gallons of coffee we had an intake manifold design like no other. By leveraging leading fuel management technology, numerous production developed components, the industry standard MEFI 4 controller and the great Ram Jet name from the 1950's, the Ram Jet 502 is a reality.

The new undisputed heavy weight champion, the Ram Jet 502, makes 502 horsepower at 5100 RPM and 565 Ft/Lbs of torque at 3200 RPM. But the real story is the torque curve, the Ram Jet 502 makes more torque throughout its operating range.

This is possible because Ram Jet has a larger plenum and runners than would ever be possible in a carbureted application. This means greater intake efficiency and greater torque without sacrificing driveability. The Ram Jet manifold is so efficient that we're able to make all of this horsepower and torque with a production L98 throttle body assembly, you know, the one that Firebird and Camaro owners always replace when trying to make more power in their 350ci engines. It's all about airflow quality, velocity, and fuel and spark management. You'll just have to drive one to appreciate it.

The Ram Jet 502 is not intended for marine use, and should only be used in 1973 and earlier pre-emissions street vehicles or any year off road vehicles. Technical Notes: Do not use bolt sealer on the cylinder head bolts, the holes are blind tapped.

502 Horsepower @ 5100 RPM
565 ft. Lbs Torque @ 3200 RPM
Maximum Recommended RPM 5800
Compression Ratio- 9.6:1

Engine Internals:

Block - 10237292 Cast iron, Gen VI, Cast iron Four Bolt Main, 1 Piece Rear Seal with Priority mains oiling
Crankshaft - 10183723 Forged 1053 Steel 4" Stroke, Nitrided and cross drilled,externally Balanced.
Connecting Rods - 10198922 4340 Forged Steel 7/16" bolts, Shotpeened, magnaflux inspected. Originally used in LS6/LS7 Engines
Pistons - 12533507 Forged, pressed pin
Camshaft - 88961447 Hydraulic Roller Intake Lift-.527" Intake Duration- 224 @ .050 Exhaust Lift-.544" Exhaust duration -234 @ .050 Lobe centerline-110
Lifters - 88961452 Hydraulic Roller
Rocker Arms - 12366082 1.7:1 Ratio,stamped steel
Cylinder Heads - 12363390 Aluminum Large Oval Port, 110cc Semi Open Combustion chamber, 290cc intake runner, 2.25"Intake valves, 1.88' Exhaust valves.
Engine Controls - 88962718 ECU- G.M. MEFI 4 Controller, self contained. New with MEFI4 closed loop speed density control.

ECU inputs consist of O2 sensor coolant temp, throttle position, manifold absolute pressure, intake manifold temp Knock sensor Signal.
ECU outputs consist of injector control, complete spark and timing control, IAC and fuel pump control.

The New MEFI 4 Controller incorporates a "green engine rev limiter" This rev limiter is set so that maximum engine rpm for the first hours of run time does not exceed 4000 rpm. Second hour 4500rpm, third hour is 4500 rpm, 4th hour and there after normal rev limiter is engaged @ 5800 rpm.

Engine also includes:

  • 8" harmonic balancer
  • 14" Automatic flexplate with standard Torque converter bolt pattern, when using 4L80E, only three bolts can be used
  • 6 Quart Truck oil pan & windage tray
  • Gear Reduction Starter
  • Small Cap HEI Ignition With external coil
  • Red GM Performance parts High Performance Spiral core plug wires with High temp Boots
  • Valve covers

Application List


Shipping Information

  • Item Requires Shipping
  • 695.0 lbs.
  • W37.0000” x H36.0000” x L42.0000”
  • Free Shipping!
  • FREE 48 State Truck Freight Shipping (International shipping will require freight quote)

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