ATK Chevy 383 Marine Stroker Engine 345HP Base HP90

Item #22643

Made in the USA
ATK Chevy 383 Marine Stroker Engine 345HP Base HP90
HP90 ATK Chevy 383 345HP Marine Stroker Base Engine Long Block
* ** THIS ITEM IS TEMPORARILY OUT OF STOCK *** FREE SHIPPING on ATK Engines. This item ships directly from the manufacturer and is not available for store pickup. Some engines are made-to-order or can be backordered. Delivery can be delayed up to 5 to 6 weeks but typically ship within 2 weeks.


Cruise down the open waters with ease by installing this ATK HP90 Chevy 383 Marine Stroker Engine 345HP Base. It uses Vortec power and stroker torque to deliver 345 horsepower and 445 torque that will keep your boat moving smoothly. This crate engine is hand built with brass freeze plugs and corrosion-resistant marine gaskets to survive offshore environment.

Engine Specifications:

  • Horsepower: 345
  • Torque: 445 lbs./ft.
  • Block: Seasoned OE 4 Bolt Main 1pc Seal Roller Block P/S Dipstick
  • Bore/Stroke: 4.040 x 3.750
  • Displacement: 383 C.I.D.
  • Crankshaft: Scat Nodular Iron 3.750" Stroke Externally Balanced Rear/Internal Front 1pc.
  • Connecting Rods: Scat 4340 Forged I Beam 5.700" ARP 8740 Bolts
  • Pistons: Hypereutectic
  • Piston Rings: Moly Rings
  • Compression Ratio: 9.5:1 Compression
  • Camshaft: Hydraulic Roller
  • Camshaft Specifications: 210/215 @050 .462in/.470ex 114LSA
  • Camshaft Bearings: Installed & Clocked to OEM Position
  • Cylinder Heads: Dart Cast Iron 67cc/165cc 2.02/1.60
  • Freeze Plugs: Brass Installed & Sealed
  • Rocker Arms: Stamped Steel 1.5 Ratio
  • Oil Galley Plugs: Installed & Sealed
  • Oil Pan: OE 5qt.
  • Weight: 350

ATK specializes in muscle. With the highest quality internal parts and Dyno Proven combinations of every engine built, ATK is able to add the most bang for your buck and back it up with an industry leading warranty.


ATK High Performance GM 383 345 HP Stage 1 Marine Long Block Crate Engines


Engine Information:

• Oil: 10W30
• Oil Filter: Wix or K&N Recommended Per Your Application
• Fuel Delivery: Quick Fuel Carburetor 680cfm #HR-680-VS or MPFI System W/Tune
• Intake Manifold: Weiand Stealth Dual Plane #8151
• Spark Plugs: Autolite #605
• Spark Plug Gap: .035"
• Harmonic Balancer/Damper: POWERBOND Internally Balanced 8" #PB1046-N
• Flex Plate / Flywheel: Externally Balanced 168 Tooth
• Timing: 34-36 Degrees Total
• Water Pump: Long Water Pump
• Firing Order: 1 8 4 3 6 5 7 2
• Fuel Pump: Holley 110GPH Mechanical #12-327-11
• Fuel: 91+ Octane
• Ignition: MSD HEI #8362


Recommended Components:

• Balancer: Internal balance
• Carburetor: Marine grade Quick Fuel 650cfm #793-M-650 (mechanical secondary's electric choke)
• Distributor: Marine grade with iron gear
• Intake Manifold: Marine grade dual plane
• Fuel Pump: Marine grade mechanical 110gph or electric fuel pupmp
• Spark Plugs: Autotile #417-605
• Spark Plug Wires: Marine grade 8mm
• Water Pump: Per application

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 for their application. Some modifications to the vehicle may be required using these and or other aftermarket parts.

Shipping Instructions

Shipping is free and lift gate will be provided.

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