383 CI SBC 525HP Airboat Engine

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The 383 525HP engine package is ideal for the airboater that is looking to replace his current small block GM 350 engine. The 388 features a 3.800 stroke crankshaft where the 350 has a 3.480 stroke. By adding the .320 stroke to the classic 350 Chevy engine it creates unbelievable low to mid range torque. When you are building or looking at re-powering your airboat low to mid range torque is what you want. Running on dry ground takes a lot of torque and power to make it happen (We have done just that). We here at Proformance Unlimited have tested many different engine combinations perfecting the perfect balance of torque and power to allow you to get the most out of your airboating experience. Designing this type of extreme duty engine goes well past just making good power and torque. We have developed several combinations that are extremely durable and will allow the user to enjoy his or her airboating experience with limited down time and maintenance.


525 & 6000


515 @ 4500

Bore & Stroke

4.030 - 3.800

  • Dart SHP 350 4.000 bore block 1pc rear main seal
  • Eagle forged steel crankshaft 3.800 stroke
  • Eagle H-Beam connecting rods with ARP bolts and bushed pins
  • High performance forged pistons (SRP, or Mahle)
  • Performance rod and main bearing (Clevite)
  • Performance rings hand filed to match application
  • ARP main bolts
  • The complete rotating assembly is balanced
  • Three piece double roller timing set
  • Custom ground hydraulic roller camshaft
  • Hydraulic roller lifters
  • AFR CNC Ported performance aluminum cylinder heads
  • (Specialty valve train designed for extreme use)
  • Screw in studs and hardened guide plates
  • Manley chrome moly push rods
  • Performance roller rockers
  • Melling high volume oil pump and screen
  • 7qt. oil pan
  • Dipstick and tube
  • Painted timing cover
  • Fel-Pro gaskets
  • Performance balancer
  • Edelbrock performance intake manifold
  • Chrome thermostat housing
  • Holley Sniper fuel injection system with inline fuel pump
  • Pro Billet distributor (Requires MSD 6AL Ignition Control)
  • MSD Blaster SS coil
  • Autolite spark plugs
  • Taylor 8mm ignition wires (color of choice Black, Red, Blue, Yellow, Green, Orange no extra charge)
  • Water pump (to match application)
  • Black valve covers
  • Breathers
  • Engines are photo documented during the building process
  • Each engine is dyno tested, timing set and carburetor adjusted for optimum performance
  • We video tape your engine and send you a copy

Does this engine look like a good fit?