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.
