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What Are the Specifications for the Discontinued BluePrint Engines BP4960 496 Big Block Chevy?

 Is the BP4960 Still Available?

No. The BP4960 is a discontinued BluePrint Engines engine package. While no longer in production, many BP4960 engines remain in service and may require maintenance, repair, or overhaul using the specifications below. What Are the Basic BP4960 Engine Specifications? The BP4960 was built as a high-displacement Big Block Chevy stroker combination featuring:

  • 496 CID Chevrolet Big Block
  • 2-piece rear main seal block
  • 2-bolt or 4-bolt Mark IV style block
  • .060" overbore
  • Forged pistons
  • I-beam connecting rods
  • Cast steel stroker crankshaft
  • Moly piston rings
  • 9.0:1 compression ratio
  • Passenger-side dipstick oil pan
  • Internally balanced rotating assembly
Is the BP4960 Internally or Externally Balanced? The BP4960 is internally balanced. The engine uses a cast steel stroker crankshaft and balanced rotating assembly.

Crankshaft Information

  • Crankshaft: SCAT 9-454-4250-6385
  • Crankshaft Assembly: C2124
  • Balance Style: Internal balance front and rear
Unlike externally balanced combinations, the BP4960 does not rely on offset-weighted balance components. What Connecting Rods and Pistons Are Used?

Connecting Rod Specifications

  • Rod Type: H-beam rods with floating pins
  • Rod Torque: 64 ft-lbs using moly lubricant
  • Bearing Tang Orientation: Tangs Out
  • Rod Bearing Clearance: Specification should be verified during rebuild using standard bearing clearance practices.

Piston Information

  • Piston Part Number: SILIC785.060
  • Piston Clearance: .0035"-.0055"
What Ring Gaps Should Be Used? The BP4960 uses:
  • Top Ring Gap: .018"-.028"
  • Second Ring Gap: .022"-.032"
Ring end gaps should always be verified during assembly. What Are the Main Bearing Specifications?

Main Cap Torque

  • 100 ft-lbs using engine oil

Main Bearing Journal Size

  • 2.7482"-2.7492"
  • Number 5 Main:
    • 2.7478"-2.7488"

Main Housing Bore

  • 2.9378"-2.9385"
Proper housing bore and bearing clearances should be verified whenever machine work is performed. What Are the Connecting Rod Journal Specifications?

Rod Journal Size

  • 2.1990"-2.2000"

Rod Housing Bore

  • 2.3247"-2.3252"
What Is the Cylinder Bore Size? The BP4960 was designed around:
  • 4.250" bore
  • .060" overbore only

Cylinder Hone Requirement

  • Torque plate honing is required.
  • Torque plate fasteners should be torqued to 65 ft-lbs during honing operations.
What Is the Deck Height Specification? Minimum deck height: 8.311" ± .001" Piston protrusion requirements:
  • Cannot be more than .003" above deck
  • Cannot be more than .005" below deck
What Oil Pressure Should I Expect?

Minimum Oil Pressure

40 PSI minimum Oil pressure can vary based on engine temperature, oil viscosity, bearing clearances, and operating RPM. Are There Special Timing Component Requirements? Yes.

Crankshaft Key Installation

The BP4960 requires:
  • Two crankshaft keys installed in the crank snout
  • Crank keys used:
    • 1AMG3
    • 98481A125
    • PK-9 (Qty. 2)
Failure to install both crank keys may prevent proper balancer drive and component retention. What Block Preparation Features Are Unique to the BP4960? The BP4960 build specification requires:
  • Late-model 454 cooling hole configuration
  • Fuel pump mounting provisions
  • 3-bolt starter pattern
  • Stroke-clearanced block
  • Brass soft plugs
  • Drilled oil galley plug on front driver-side oil galley
  • Black engine paint finish
These requirements were part of the original BluePrint assembly procedures.