Detroit Diesel Engines, what is the difference between a Long Block, 3/4 Engine, and PowerChoice engine?
Posted by: Duaparts on
When shopping for remanufactured or replacement engines, you’ll often come across terms like Long Block, 3/4 Engine, and PowerChoice Engine. Each of these options provides a different level of components, coverage, and cost depending on what you need.
Here’s a breakdown:
Long Block
Key Benefits:
Built to generic specification
Fast delivery (common models kept in stock)
Lowest cost option
Includes only base engine components
Main Parts Included:
Engine Block, Crankshaft, Pistons, Cylinder Head, Camshafts
Gear Train, Flywheel & Housing, Rocker Cover
Lubrication & cooling parts like Oil Pan, Water Pump, Oil Cooler, Filters
Best for: Budget-conscious buyers who only need the base engine rebuilt.
3/4 Engine
Key Benefits:
Still built to generic specification
Faster delivery, with better coverage than Long Block
More budget-friendly than full engine replacements
Additional Parts (on top of Long Block):
Vibration Damper
Fuel Injectors, High-Pressure Fuel Rail, Injector Lines
Best for: Fleets or operators who need essential fuel system components included but want to avoid the cost of a complete engine.
PowerChoice Engine
Key Benefits:
Built to serial number specification (matches original build)
Ideal for scheduled repowers
Dyno-tested for performance
Fastest repair time and the most comprehensive coverage
Additional Parts (on top of 3/4 Engine):
Alternator Brackets, Rocker Arm Assemblies
Engine Harness & ECM
Full fuel system: High-Pressure Fuel Pump, Filter Module, Fuel Lines, Injector Harness
Air & Exhaust system: Air Intake, Compressor, Exhaust Manifold, EGR Cooler, Turbocharger
Best for: Those who want a complete, ready-to-install, dyno-tested engine with maximum reliability and coverage.
Coverage Options:
Long Block: 1 Year / 100,000 miles coverage
3/4 & PowerChoice:
1 Year / 100,000 miles
2 Year / 200,000 miles (StepUP)
3 Year / 300,000 miles (StepUP)
In short:
Long Block = Basic, lowest-cost solution
3/4 Engine = Adds key fuel system components
PowerChoice = Complete engine with full systems, best coverage