The Boostline Performance BL427JLB Street-Strip Series 427 long block has all the ingredients to pack the punch you're looking for. Our 427 LS combo is a proven performer and a solid foundation for your ride.

Plan to clear 800HP NA with the right cam and intake selection! This package is still dependable at the 1000HP mark if you want to put a little extra squeeze on it with your choice of power adder.

Boostline Performance BL427JLB Specs:

• GM Aluminum Gen IV 5.3L Block with Darton Sleeves
• Blocks are CNC Decked, CNC Bored and CNC Torque Plate Honed and Align Honed
• Boostline Center Counterweighted Forged 4 in. Stroke Crank
• Forged 6.125 in. H-Beam Rods with ARP bolts
• Forged 2618 Flat Top Pistons
• Aluminum LS3-Style Rectangle Port 238cc Cylinder Heads
• Hydraulic Roller Camshaft:
  • Duration @ .050 in. 23x Intake/25x Exhaust
  • Lift: .59x Intake/.59x Exhaust
  • Note: Camshaft duration and lift values are shown with the final digit omitted to protect proprietary camshaft profiles. Boostline Performance uses lobe designs developed for this engine, and its intended performance range and operating characteristics
• LS7 Lifters and Trays
• Single roller Billet Gear, performance, timing chain & gear set
• Billet timing chain dampener, also added to all gen3 builds
• Pushrods, one-piece - hardened, 3/8 in.
• GM Rockers built with bronze bushing-style trunnion kits
• New Rocker Arm Bolts
• ACL Main & Rod Bearings
• Durabond Cam Bearings
• New block plug kit and barbell
• Melling High Volume Oil Pump
• ARP Main Studs
• ARP Head Studs
• Fel Pro Gaskets Throughout
• BTR LS9 head gaskets
• Boostline Valve Covers with coil mounts
• GM muscle car oil pan and pickup tube
• GM stock front cover
• GM stock rear seal housing

Boostline Performance BL427JLB Features:

• Fully assembled long block engine
• Includes cylinder heads and valvetrain components
• Professionally assembled for street and street-strip performance applications

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