ATK HP98M Chevy 350 Mid Dress Engine 345HP



Lead Time: Estimated: 4 - 6 weeks


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Engine Specifications:
• HP: 345
• TQ: 400
• Block: OE block 4 bolt main 1pc seal 1987-2000
• Bore/Stroke: 4.040 x 3.480
• Displacement: 350
• Crankshaft: OE Reground external balance rear of crank/internal balance front of the crank
• Rods: OE powder metal 5.7”
• Pistons: Hypereutectic 9.1:1 compression
• Rings: Moly
• Camshaft: Hyd. roller
• Cam Specs: 220/224 @50 .495in/.502ex 110LSA
• Timing Chain: Double roller
• Cylinder Heads: ATK cast iron 76cc/165cc 1.94/1.50
• Rocker Arms: Stamped steel 1.5 ratio
• Oil Pan: Rear sump 5qt (not for Chevelles with steering behind crossmember, some corvettes and 62-67 chevy II’s)
• Oil Pump: Melling high volume
• Balancer: PowerBond internal balance 8” #PB1046-N
• Flexplate/Flywheel: Pioneer #FRA-159 external balance 168 tooth
• Intake Manifold: ATK dual plane intake
• Distributor: HEI (Iron gear)
• Water Pump: OE long pump

Recommended Components:
• Carburetor: Quick Fuel 680CFM vacuum secondary’s with electric choke #HR-680
• Fuel Pump: Holley mechanical 110GPH #12-327-11
• Spark Plugs: Champion #RV12C
• Spark Plug Wires: 8mm

Engine Info:
• Oil: Conventional / Non synthetic 10W30 with Comp Cam zinc additive #159 for first 3000 miles
• Oil Filter: Wix or K&N per application
• Timing: 34-36 Degrees
• Spark Plug Gap: .035”
• Firing Order: 18436572
• Octane: 91+
• Stall Converter: 2200-2500
• Exhaust: 1 5/8 Headers


Disclaimer: The parts listed are ATK’s recommendations of parts to be used to obtain our power figures listed. Power figures can vary based on parts used by the end user. It is the customer’s responsibility to verify components will work in their application. Some modifications to the vehicle may be required using these and or other aftermarket parts. ATK reserves the right to substitute parts used in engines if necessary.


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