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 Small Block Chevy 350ci engine, except 1992-1997 LT1 style engines
A great 350 crate engine with noticible idle, but still maintains good vacuum for all your power accessories.
- Horsepower: 350 hp
- Torque: 400 lb/ft
- Seasoned OE 4 bolt main 1pc seal 1996-2000
- Bore/Stroke: 4.040" x 3.480"
- Displacement: 350ci
- Crankshaft: OE Reground 1 piece seal crank
- Balance: External rear, internal front
- Rods: OE powder metal 5.7"
- Compression Ratio: 9.5:1
- Pistons: Hypereutectic
- Rings: Moly
- Camshaft: Hydraulic roller
- Cam Duration @ .050": Intake 220 / Exhaust 224
- Cam Lift: Intake .495" / Exhaust .502"
- Lobe Separation Angle: 110lsa
- Timing Chain: Double roller
Cylinder Head Information:
- Cylinder Heads: Vortec cast iron
- Combustion Chamber: 67cc
- Valve Size: 1.94" Intake / 1.50" Exhaust
- Rocker Arms: Stamped steel 1.5
Oil Pan Information:
- Oil Pan: Rear sump 5qt (not for Chevelles with steering behind crossmember, some Corvettes, and 1962-1967 Chevy II's
- Oil Pump: Melling standard volume
- Short Block
- Timing Set
- Cylinder Heads
- Valve Covers
- Timing Cover
- Oil Pan
- Oil Pump & Pickup Tube
- Exhaust: 1-5/8" Headers
- Firing Order: 18436572
- Octane: 91+
- Oil: 10W30 (Conventional / Non Synthetic)
- Oil Filter: Wix or K&N
- Spark Plug Gap: .035"
- Stall Converter: Stock
- Timing: 34-36 Degrees
- Balancer: Internal balance
- Carburetor: Quick Fuel 680cfm vacuum secondary electric choke #793-HR-680-VS
- Distributor: HEI (iron gear)
- Flexplate/Flywheel: External balance 1987-Up
- Intake Manifold: Edelbrock Performer RPM #350-7116
- Fuel Pump: Holley Mechanical 110gph #510-12-327-11
- Spark Plugs: Autotile #417-605
- 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.
In 2007, ATK launched a High Performance Division with one of the finest engine shops in the country. By reverse engineering all of their engines, they are able to eliminate any OEM deficiencies. This makes an ATK built crate engine have a superior design over the original engine by incorporating better components when needed. These quality built engines are offered in three different stages for ease of finishing an engine swap. ATK HP engines feature a 24 month/unlimited mile warranty.
Does this motor come with a dyno report? Also will it drop into a 72 stingray or will I need to change the oil pan
Why does the required components list an external balance flexplate but an internal balance harmonic balancer?
Will this fit a 1993 GMC Sierra C1500? If so, where would I buy the computer chip?
Someone told me from there that the HP 98 won't work on my 1990 Blazer how about this HP 32 will it work? And that person told me the HP 31 will work but I don't like the horsepower.
will this block fit a 1979 z-28 with stock manifold and auto transmission
will this fit a 1977 corvette with (L40) 350ci
Is this a direct bolt in for a 1977 L82 corvette with a turbo 400 transmission
Will this bolt up to a M/S 465 Manual transmission (4spd) from a '77 4x4 (aleady mated to a NP 205 transfer case?
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.