JE Pistons · New
JE Pistons Subaru EJ257 Ultra Series 8.5:1 Comp, 99.75mm Bore, 83mm Stroker Piston Kit (Set of 4)
MPN 378135 · Store SKU jep378135
Supplier stock checked 11/7/2026, 9:17:37 AM UTC. Adding a part does not reserve it.
Request a return within 30 calendar days after delivery. New parts must be unopened and unused.
Shipping & returns ↗This policy does not limit rights required by law.Free standard shipping on eligible parts orders of $100 or more. Oversized and freight items excluded. Fitment, taxes, availability and final totals are confirmed before payment.
Product details
Ultra Series forged pistons from JE are the industry’s strongest, most fully featured pistons available off the shelf. Offered for Subaru STI EJ257 Engines. Ultra Series Pistons feature JE’s proprietary Aligned Grain Flow forging technology providing next-level tensile strength ideal for the extreme cylinder pressures of power adder engine builds. Equipped with the following custom level features Accumulator Groove, Smooth Crown Finish, Pin Fit, Thermal Crown, Lateral Gas Ports, and Skirt Coat. Ultra Series pistons are made 100% in the USA. 99.75 mm Bore - 28.70 mm CD - (-21.10 cc) - 4 Cyl. Piston Kit Ultra Series - Subaru EJ257 Piston Kit - 99.75/28.70/-21.10
Manufacturer fitment & guides
Check 378135 against the manufacturer’s application information below.
A manufacturer application guide is not available for this listing. Request the exact application from JuiceBuilt before payment.
Part-specific notes
- Not CARB approved. Destination and intended-use restrictions must be checked before sale.
- Emissions acknowledgement required before purchase.
- California Proposition 65: Y
