Carrillo SC7438-4 Forged Piston Set Subaru EJ257 WRX STI Stroker 99.75mm 9.0:1

Designed for high-output forced induction and naturally aspirated stroker applications, these pistons displace approximately 2.6–2.7 liters depending on final bore size.

Key Specifications:

• Bore Size: 99.75mm (+0.25mm over stock)
• Stroke: 83mm (stroker application)
• Compression Ratio: 9.0:1
• Compression Height: 1.123"
• Dome: +0.25mm
• Rod Length: 130.5mm

Key Features:

• Forged from high-strength 2618 aluminum alloy for exceptional durability under high power output
• Precision-machined to exacting tolerances using computerized CNC processes
• Includes file-to-fit rings — must be filed to the correct ring gap for your specific application before installation
• Compatible with stock and oversized valves as well as stock and high-lift camshafts
• Available with optional upgrades: gas ports, skirt coating, ceramic top coat, and upgraded wrist pins (order separately)
• Factory wrist pin locks are used — no locks supplied

Because the bore size is larger than stock, the cylinder block must be bored to match these pistons. It is strongly recommended that the block not be bored until the machine shop has the pistons in hand. Ring gap must be set by a qualified engine builder prior to installation, as optimal gap varies significantly based on power level and intended use.