ATK Core Return Process
JEGS and ATK appreciate your business and want to ensure that your core return is as smooth as possible.

Please CLICK HERE for ATK Core Return Process

NOTE:

• Core return must be a 1996-2000 350ci Vortec Truck/SUV engine

Engine Specifications

Power Ratings:

• Factory Specs
  • Horsepower: 255 hp 
  • Torque: 330 ft.-lbs.

• Carbureted
  
  • Horsepower: 290 hp*
  • Torque: 375 ft.-lbs.

*Carbureted engine was tested using a performance dual plane intake manifold, 670 cfm carburetor, and an HEI distributor.

Block Information:

• 1996-2000 seasoned OE block
• 2-bolt main
• 1-piece rear main seal
• Passenger side dipstick 
• Displacement: 350 ci, 5.7L

Rotating Assembly:

• Crankshaft: OE reground cast 1 piece seal
• Balance: External rear, internal front
• Rods: OE reman powder metal 5.7 in.
• Compression Ratio: 9.6:1
• Pistons: Cast
• Rings: Moly

Camshaft Specs:

• Camshaft: Hydraulic roller
• Cam Duration @ .050 in.: Intake 191 / Exhaust 194
• Cam Lift: Intake 0.414 in. / Exhaust 0.428 in.
• Lobe Separation Angle: 112 lsa
• Timing Chain: Single roller

Cylinder Head Information:

• Cylinder Heads: Vortec cast iron
• Combustion Chamber: 64 cc
• Intake Runner: 165 cc 
• Valve Size: 1.940 in. Intake / 1.500 in. Exhaust
• Rocker Arms: Stamped steel 1.5

Oil Pan Information:

• Oil Pan: Black 4 quart
• Oil Pump: Melling standard volume

 Long Block Includes

• Short Block
• Camshaft
• Timing Set
• Cylinder Heads
• Valve Covers
• Timing Cover
• Oil Pan
• Oil Pump & Pickup Tube

 Notes: Does not have mechanical fuel pump provisions.

Engine Break-In Procedure

Use conventional or break-in oil (non-synthetic) for the first 600 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. Check the engine oil and coolant levels daily. 

At 600 Miles change the engine oil and filter using conventional (non-synthetic) oil. Check fuel and ignition settings; adjust valves (where applicable).

After the first 5,000 of service synthetic engine oil may be used. Follow your vehicle owner’s manual for service intervals.

Please CLICK HERE for ATK Warranty