ATK HP90 Chevy 383 Vortec Marine Base Engine 345HP



Lead Time: Estimated: 4 - 6 weeks


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Engine Specifications:
• HP: 345
• TQ: 445
• Block: OE roller block 4 bolt main 1pc seal 1996-2000
• Bore/Stroke: 4.040” x 3.750”
• Displacement: 383CI
• Crankshaft: Scat Nodular Iron external balance rear of crank/internal balance front of the crank
• Rods: Scat I Beam 5.7” Rods with ARP 8740 Bolts
• Pistons: Hypereutectic 9.5:1 compression
• Rings: Moly
• Camshaft: Hyd. roller
• Cam Specs: 210/215 @50 .462in/.470ex 112LSA
• Timing Chain: Double roller
• Cylinder Heads: Dart vortec cast iron 67cc/165cc 2.02/1.60
• 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 STD volume
• Flexplate/Flywheel: Externally balanced – Pioneer #FRA-159 (with scat kit) or Flywheel depending on application

Recommended Components:
• Balancer: Internally balanced – PowerBond #PB1046-N or per application
• Intake Manifold: Marine grade dual plane
• Distributor: Marine grade pro billet (iron gear)
• Water Pump: Per application
• Carburetor: Marine grade Quick Fuel 650CFM mechanical secondary’s electric choke #M-650
• Fuel Injection: Can be used with MPFI, but custom tuning required to ECM.
• Fuel Pump: Marine grade 110GPH mechanical or an Electric fuel pump
• Spark Plugs: Autolite #605
• Spark Plug Wires: Marine grade 8mm per application

Engine Info:
• Oil: Conventional / Non Synthetic 10W30
• Oil Filter: Wix or K&N
• Timing: 34-36 Degrees
• Spark Plug Gap: .035”
• Firing Order: 18436572
• Octane: 91+
• Stall Converter: Stock
• Exhaust: 1 5/8 Headers or stock manifolds

Notes: This is a MARINE engine. The bearing clearances and camshaft profile are designed for marine use. Not intended for automotive applications.


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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