Chevrolet Performance Bowtie Sportsman Engine Block 400 Main 350 Bore w/ 4-Bolt Main/ 2-Piece Rear Main

Get the power you need for street/strip performance from Chevrolet Performance! Their 400 main and 350 bore engine block (12480049) is a solid foundation for 350-500 horsepower applications. It supports and has siamesed cylinder walls, providing strong and reliable stability under load. Plus, it avoids sealing issues thanks to the extra-thick deck surfaces with blind-tapped holes.

Features and Benefits:
- Compatible with 350-500 horsepower applications
- Great for street/strip, drag strip, circle track, and high-performance street builds
- CNC-machined cast-iron competition block
- Designed with priority main oiling for more stable oil pressure
- Siamesed cylinder walls increase block strength and cylinder stability
- 2-piece rear main seal provides reliable sealing
- 4-bolt nodular mains provide increased crankshaft stability under load
- Center three main caps are splayed for stronger bottom-end rigidity
- Caps are secured with grade 8 bolts
- Extra-smooth gasket surfaces for better seal
- Extra-thick deck surfaces have blind-tapped bolt holes for better head gasket sealing
- Minimum cylinder wall bore thickness on 4.155" bore is 0.225"
- Tall lifter bores help keep lifters stable under high spring pressure

Specifications:
- Casting number: 10051184
- Crank journal size: 400
- Deck height (standard): 9.025"
- Lifter pattern: standard
- Bore range: 3.980" to 4.155"
- Main bolt degree: 20 degrees
- Nominal cylinder wall thickness: 0.340"
- Oiling system: wet sump
- Max stroke: 3.750"
- Main bearing bulkheads: 0.900" thick
- Machining tolerance: +/-0.001"
- Weight: 208 pounds

Additional Notes:
- All five cam bearing locations require 2.000" O.D. (1.867" I.D.) bearings.
- The top of the tall lifter bore blocks may require clearancing for some roller lifters.
- There is a lifter valley oil scavenging boss below bell housing flange present, but it is not drilled or tapped.
- Oil dipstick holes are not drilled.
- Timing system clearance must be checked.