5.9L Long Block Model C Engine Choate Performance 1989-1993-Cummins Dodge Diesel Engine Choate Performance

The “Model C” is a budget-friendly build designed for those looking for an engine close to stock in power but with the common issues fixed.

Key Features and Fixes

• Upgraded Pistons: Upgraded pistons that are inherently stronger and designed for more robust commercial applications. This solves the OEM issue of weak pistons that are prone to cracking under heat and boost.
• Enhanced Valve Integrity: Features all-new, upgraded material valves that eliminate the high-heat separation common in OEM exhaust valves, preventing compression loss and piston-to-valve contact.

Machining Process:

Choate Engineering Performance doesn’t just rebuild engines - we remanufacture them. Each of our engines undergoes extensive, precision machine work to correct OEM flaws and ensure durability and reliability.

Engine Block Machining:

Each of our engine blocks are CNC blueprint machined using state-of-the-art CNC machines. This process ensures perfect dimensions, precise tolerances, and optimal alignment. This starts with decking the surface of the block to achieve the necessary flatness and smoothness (Ra 30 or better) required for flawless sealing with MLS head gaskets. The cylinders are then diamond honed to an extremely tight tolerance to match the piston diameter (within the nearest 0.0001 inch). Following honing, the main bearing bores are line honed to establish a true, straight centerline for the crankshaft. Finally, the cylinder bores are bored to a true 90 degree angle from the crankshaft centerline.

Cylinder Head Machining:

Our cylinder heads are fully machined and enhanced in-house to improve airflow and reliability. Each head is first magnafluxed and pressure tested to ensure they are free of any cracks or leaks. The surface is then precision decked to an extremely smooth finish, guaranteeing the necessary flatness for a perfect seal with MLS head gaskets. Internally, the valve seats are machined to optimize airflow and prevent common failures, and the entire valve train geometry is blueprinted to specific tolerances to reduce lifter preload and prolong component life.

Components and Parts:

Engine Core Components

• Cylinder Block
• Crankshaft
• Steel Connecting Rods
• Camshaft
• New Pistons
• Reman Cylinder Head
• New Main Bearings
• New Rod Bearings
• New Cam Bearings
• Main Bolts
• Head Bolts
• Billet Freeze Plugs
• New Oil Pump

Gaskets and Seals

• New Head Gaskets

Cylinder Head Components

• New Valve Guides
• New Socket Plug
• New Oversized Valve Seats
• New Threaded Plugs