TSP 427ci 7.0L Resleeved LS Short Block

TSP 427 C.I.D. / 7.0L Resleeved Gen IV LS Short-Block

The Texas Speed & Performance 427 C.I.D. / 7.0L Resleeved Gen IV LS Short-Block is a proven, high-performance combination built for customers who want serious power without waiting for a fully custom engine build. Starting with a SEASONED Gen IV 5.3L Aluminum block, each block is resleeved to a 4.125″ bore and combined with a 4.000″ stroke rotating assembly to produce 427 cubic inches.

Each short-block is machined and assembled at Texas Speed & Performance using the same processes, equipment, and attention to detail as our custom engine program. The rotating assembly is balanced, critical clearances are verified, and the complete short-block is assembled to TSP specifications.

Short-Block Configuration

• Displacement: 427 C.I.D. / 7.0L
• Block: SEASONED/CORE GM Gen IV 5.3L LS Block
• Bore: 4.125″ Resleeved Block
• Stroke: 4.000″
• Crankshaft: TSP Forged 4.000″ Stroke Crankshaft
• Reluctor Wheel: 58x
• Connecting Rods: Forged 4340 Steel H-Beam Rods
• Rod Length: 6.125″
• Pistons: Forged Pistons with Available -2.8cc or -18cc Configuration
• Main Fasteners: ARP Main Stud Kit

Forged Rotating Assembly

The forged 4.000″ stroke crankshaft, 4340 steel H-beam connecting rods, and forged pistons create a strong rotating assembly for serious naturally aspirated, nitrous, supercharged, and turbocharged combinations.

Choose between the available -2.8cc and -18cc piston configurations based on your cylinder heads, desired compression ratio, fuel, intended use, and whether the engine will be naturally aspirated or used with a power adder.

Power Capability

This short-block is built for combinations targeting up to 1,000 horsepower. Actual power capability and engine life will depend on the complete engine combination, compression ratio, cylinder heads, fuel system, power adder, calibration, operating conditions, and quality of the final installation.

Built and Machined In-House

Critical machining and assembly operations are performed at the Texas Speed & Performance engine machining facility. Each block and rotating assembly is inspected, measured, balanced, and assembled as a complete package to ensure the proper fit and clearances.

Important 58x Reluctor Information

Important Notes

• This listing is for a 427 C.I.D. / 4.125″ bore x 4.000″ stroke short-block.
• Black Friday pricing begins at 12:01 a.m. Central Time on November 27, 2026.
• The advertised sale price is not available before the sale begins.
• Final compression ratio will depend on piston selection, cylinder-head chamber size, head-gasket thickness, and deck height.
• Verify piston compatibility, compression ratio, and all critical clearances with the complete engine combination.
• All short-blocks are supplied with a 58x crankshaft reluctor wheel.
• A crankshaft-signal conversion box is required for compatible 24x Gen III applications.
• Final tuning and calibration are the customer’s responsibility.
• Professional installation and tuning are strongly recommended.