Overview:

When you’re building big power, you need a block that’s ready to carry the load—and this BBC-compatible foundation is engineered to take you all the way to a massive 598 cubic inches. Designed for serious street, strip, and marine performance, this block delivers the strength, rigidity, and machining precision needed for high-horsepower combinations. Thick cylinder walls, robust main webbing, and smartly engineered oiling and cooling pathways give builders the confidence to push displacement and power further without sacrificing reliability. Whether you’re crafting a torque-heavy cruiser or a high-rpm bruiser, this block is the rock-solid starting point your big-inch Chevy build deserves.

Cylinder Bore (Rough):

• 4.239" to 4.241"

Cylinder Bore (Max):

• 4.630"

Cam Bearings:

• Durabond GM-12

Cam Bearing Bore ID:

• 2.120"+/- .001"

Camshaft Position:

• OEM

Cam Drive / Timing Set:

• OEM / Double Roller

Cam Retaining Plate:

• OEM

Cubic Inch (Max):

• 598

Cylinder Wall Thickness:

• .310" Nominal @ Max Bore

Cylinder Skirt Length:

• 6.300" Nominal

Deck Height:

• 9.800" +.005" / -.000"

Deck Thickness:

• .710" Nominal

Freeze / Core Plugs:

• 1-5/8" x 8

Head Bolt / Stud Threads:

• 7/16-14 UNC

Lifter Bores:

• .8437" +/- .0003"

Lifter Retainer (If not using tie car lifters):

• OEM W/Roller Provisions

Main Bearing Bore (Line Honed):

• 2.937" - 2.938"

Main Bearing Caps:

• Billet Steel

Main Cap Bolts:

• 1/2"-13 UNC

Main Fastener Tensile Strength:

• 180,000 to 210,000 PSI

P1 Main Stud Kit P/N:

• TBD

ARP Main Stud Kit P/N:

• TBD

Material (Block):

• EN-GJL-250 Iron

Oil System:

• Priority Main

Oil Pump:

• OEM

Oil Filter:

• OEM

Oil Pan:

• OEM (GEN IV)

Rear Main Seal:

• 2 piece - Seal (OEM GEN IV)

Starter:

• OEM

Stroke (Max):

• 4.750"

Timing Cover:

• OEM GEN IV

Approx. Weight with Main Caps:

• 240-260lbs