ATK Core Return Process
JEGS and ATK appreciate your business and want to ensure that your core return is as smooth as possible.
- Core return can be any Big Block Chevy 454ci engine
- Horsepower: 565 hp
- Torque: 595 lb/ft
- Seasoned OE 1991-1995 Gen V 4 bolt main 1pc seal (no mechanical fuel pump provision)
- Bore/Stroke: 4.310" x 4.250"
- Displacement: 489ci
- Crankshaft: Scat nodular iron
- Balance: Internal
- Rods: Scat 4340 forged I beam 6.385" with ARP 8740 Bolts
- Compression Ratio: 10.1:1
- Pistons: Forged
- Rings: Moly
- Camshaft: Hydraulic roller
- Cam Duration @ .050": Intake 237 / Exhaust 243
- Cam Lift: Intake .635" / Exhaust .640"
- Lobe Separation Angle: 112lsa
- Timing Chain: Double roller
Cylinder Head Information:
- Cylinder Heads: Edelbrock E-Street aluminum
- Combustion Chamber: 110cc
- Intake Runner: 290cc
- Valve Size: 2.19" Intake / 1.88" Exhaust
- Rocker Arms: Billet aluminum roller rockers 1.7 ratio
Oil Pan Information:
- Oil Pan: OE 5qt
- Oil Pump: Melling high volume
- Short Block
- Timing Set
- Cylinder Heads
- Valve Covers
- Timing Cover
- Oil Pan
- Oil Pump & Pickup Tube
Mid Dress Engines
- Consists of Base Engine Build
- Intake Manifold
- Water Pump
- Harmonic Balancer
- Consists of Mid Dress Engine Build
- Fuel Pump
- Spark Plug Wires
- Spark Plugs
- Exhaust: 2" Headers
- Firing Order: 18436572
- Octane: 91+
- Oil: 10W30 (Conventional / Non Synthetic)
- Oil Filter: Wix or K&N
- Spark Plug Gap: .035"
- Stall Converter: 2800+
- Timing: 34-36 Degrees
- Balancer: Internal balance 8"
- Carburetor: Quick Fuel 780cfm vacuum secondary electric choke #793-HR-780-VS
- Distributor: HEI (iron gear)
- Flexplate: Internal balance
- Fuel Pump: No mechanical fuel pump provision, must run an electric pump
- Intake Manifold: Edelbrock Performer RPM dual plane #350-7161
- Spark Plugs: Autotile #417-3923
- Spark Plug Wires: 8mm
- Water Pump: OE long pump
Disclaimer: The parts listed are ATK's recommendations of parts to be used to obtain the power figures listed. Power figures can vary based on parts used by the end user. Some modifications to the vehicle may be required using these and or other aftermarket parts.
Engine Break-In Procedure
Use or break-in oil or conventional (non-synthetic) 10w30 oil with zinc additive for the first 500 miles of operation. Do not drive for long periods at any single speed, always vary your speed. Do not tow a trailer or put other heavy loads on the vehicle. It is best to avoid long periods of idling during this period. Check the engine oil and coolant levels daily.
Engines with flat tappet hydraulic cams only - Run the engine between 2,000 and 2,500 RPM's, with no-load on the engine for the first 30 minutes. Let the engine cool down completely and repeat process 2-3 more times. Do not idle the engine for any extended period at this time, this is critical to break in the camshaft.
At 500 Miles change the engine oil and filter using conventional (non-synthetic) oil with a zinc additive. Check fuel and ignition settings, adjust valves (where applicable). Drive the next 500 miles normally, without high RPM's (below 5000 RPM), hard use, or extended periods of high loading or long periods of idling.
Change the oil and oil filter again at 1,000 miles. Continue using conventional (non-synthetic) oils and zinc additive, until about 4,000 miles. At that point, you may run a quality 10w30 synthetic oil if you choose. Use of oil with zinc or a zinc additive for the life of your engine is recommended.
The details have a note saying that you can’t run a mechanical fuel pump it must be electric but the overview says it comes with the mechanical fuel pump and the picture shows it having a mechanical fuel pump. Which is correct?
WARNING: Motor vehicles contain fuel, oils and fluids, battery posts, terminals and related accessories which contain lead and lead compounds and other chemicals known to the State of California to cause cancer, birth defects and other reproductive harm. These chemicals are found in vehicles, vehicle parts and accessories, both new and as replacements. When being serviced, these vehicles generate used oil, waste fluids, grease, fumes and particulates, all known to the State of California to cause cancer, birth defects, and reproductive harm.
WARNING: Some dust created by power sanding, sawing, grinding, drilling, and other construction activities contains chemicals known to the State of California to cause cancer and birth defects or other reproductive harm. Some examples of these chemicals are: lead from lead-based paints, crystalline silica from bricks and cement and other masonry products, and arsenic and chromium from chemically treated lumber. Your risk from exposure to these chemicals varies, depending on how often you do this type of work. To reduce your exposure, work in a well-ventilated area and with approved safety equipment, such as dust masks that are specially designed to filter out microscopic particles.
WARNING: The wires of these products contain chemicals known to the State of California to cause cancer and birth defects or other reproductive harm. Wash hands after handling.