Type: LS7 7.0L FI
Displacement: 427 Cubic Inches
Compression Ratio: 9.5:1
Bore x Stroke: 4.130 x 4.000
Rev Limit: 7000 RPM
Crank: Callies Dragonslayer
Rods: Callies H-Beam
Pistons: Mahle Motorsports 2618
Cam: Mast 3-Bolt Core Cam
Heads: Mast Black Label LS3 280 Heads
Valve Springs: Mast Dual
*All hp numbers will be within 2% of the advertised number.
Mast Motorsports Handbuilt LS engines feature the best components and are assembled by professional machinist. All handbuilt engines feature ARP Main Studs, ARP Head Bolts or Studs and a balanced and blueprinted block.
The LS7 427 Black Label 900's heart and soul is the new 4.125 aluminum block. This monster LS7 has a Mast Motorsports engineered camshaft that is custom ground on a Mast Motorsports LS7 cam core. The 427 foundation is a honed and decked LS7 aluminum block with a 4.000” forged Callies Dragonslayer rotating assembly with Mahle pistons that is topped off with Mast Black Label LS3 280 heads. ARP fasteners are used throughout and Mast pushrods ride on GMPP High RPM hydraulic roller lifters. The LS7 427 Black Label 900 is at the top of of a diverse line of Mast Motorsports handbuilt LS7 based built for boost long blocks that are designed for the Hot Rod/Muscle Car market. The LS7 427 Black Label FI engine is capable of hitting the 900 horsepower mark and is one of the most power capable LS7 based long blocks available.