Chevrolet Performance 19434240:

• New Design Casting Taking the Best of Both MarkIV and GenVI Designs
• Production Type Cast-Iron 4-Bolt
• Block Improved Main Bearing Bulkheads with Bowtie Block-Style Bulkhead
• Clearanced for Larger Strokes
• 4.470 Inch Finished Bore
• 4.500 Inch Max Bore (Siamese)
• Fuel Pump Pad Added/Machined
• Water Jackets for Either MarkIV or GenVI Heads
• Revised Oiling to Allow Bigger Cam Bearings and Lift
• Bolt Boss is Machined, Adding Near Distributor Hole Like 8.1L
• Can be Drilled for Use with 10-Bolt Front Cover
• Auxiliary Oil Pressure Line Added to Front of Block
• Racing Style Oil Filter Cast Feature with Added Oil Pressure Port
• Two Bosses Added for Manual Transmission Clutch Pivot
• Additional Materiel Added Around Lifter Bosse

Emissions Note:

This part is only legal for sale and use on Uncontrolled (Non-Emissions Controlled) Vehicles or on vehicles used solely for the purposes of closed competition racing.

CLICK THIS LINK FOR IMPORTANT CARB & EPA EMISSIONS INFORMATION ABOUT THIS PART