TSP 427 Dart LS Long Block

Texas Speed 427 Dart LS Long Block

Take your performance to the next level with the Texas Speed & Performance 427 CID Dart LS Long Block — a turn-key powerhouse built for high-horsepower street, strip, and track applications. Featuring the robust foundation of a Dart LS Next iron block and fortified with a premium valvetrain and top-end components, this engine is capable of supporting up to 1200 horsepower while maintaining street-friendly drivability.

Long Block Build Specifications:

• Displacement: 427 CID
• Block: Dart LS Next Iron Block, 6-bolt configuration
• Crankshaft: TSP 58x 4.00” Stroke Forged Crankshaft
• Pistons: TSP/Wiseco 4.125” Forged Pistons (-13cc) w/ upgraded wrist pins
• Rods: TSP 4340 Steel 6.125” I-Beam Connecting Rods
• Main Fasteners: ARP Main Stud Kit
• Heads: PRC 260cc CNC-Ported LS3 Cylinder Heads (Stainless Valves)
• Head Studs: Dart 1/2” Head Stud Kit for extreme clamping force
• Camshaft: TSP LS3 Stroker Turbo Cam
  • Duration @ .050” – Intake: 235° / Exhaust: 250°
  • Lift – Intake: .644” / Exhaust: .632”
  • LSA: 114°, ICL: 112°
• Lifters: Johnson 2116 LSR Hydraulic Roller Lifters
• Compression Ratio: 10.5:1 — ideal for turbocharged or NA builds
• Horsepower Rating: Capable of supporting up to 1200 HP

Dyno-Proven Results at Texas Speed

This exact engine combo was developed and proven in-house here at TSP. We’re including a dyno sheet showing 1200 horsepower achieved on our engine dyno using this long block paired with:

• TSP Stealth Low-Profile Intake Manifold
• Twin Pulsar 6866G Turbochargers
• Flowtech 1-7/8” Turbo Headers
• CX Racing Air-to-Water Intercooler (105°F IAT average)
• VP Racing X85 Fuel

The dyno pull began at 7 PSI and ramped to 20 PSI at peak power, delivering broad torque and smooth power across the curve. This combination is fully tested, repeatable, and track-proven.

Performance & Application

Perfect for turbocharged setups, nitrous builds, or aggressive naturally aspirated combinations, this long block is ideal for street-driven performance builds, competitive drag cars, and serious track projects. Whether you’re chasing records or just dominating your local scene, the TSP 427 Dart LS Long Block has you covered.

Built to Perform — Proven to Deliver

Backed by real-world dyno data and TSP’s reputation for quality, this long block is your key to a high-horsepower LS platform that doesn’t just promise performance — it proves it.