GSC Power Division 2064-12 +1mm Oversized Intake Valves for Toyota 2JZ-GE/GTE

Vehicle Fitment

• 1993-1998 Toyota Supra (2JZ-GTE Twin Turbo, RWD)
• 1993-1998 Toyota Supra (2JZ-GE Naturally Aspirated, RWD)
• 1993-2005 Lexus GS300 (2JZ-GE, RWD)
• 1992-2000 Lexus SC300 (2JZ-GE, RWD)
• 2001-2005 Lexus IS300 (2JZ-GE, RWD)
• 2001-2005 Lexus IS300 SportCross (2JZ-GE, RWD)

Fitment Notes

• Fits both the 2JZ-GTE (twin turbocharged) and 2JZ-GE (naturally aspirated) variants - the intake valve specifications are shared across both engine configurations
• +1mm oversized head (34.50mm) - requires valve seats to be machined to match; not a drop-in replacement for standard 33.50mm seat heads without seat cutting
• For heads with standard (uncut) seats, use GSC part number 2062-12 (STD 33.50mm intake valves)
• Sold as a set of 12 - one complete engine set for the inline-6 (2 intake valves per cylinder x 6 cylinders)
• Verify the cylinder head has been properly machined for +1mm oversized valve seats before ordering

Features

• Modified 21-4N stainless steel alloy construction provides excellent strength, heat resistance, and long-term durability in both naturally aspirated and turbocharged 2JZ applications
• +1mm oversized 34.50mm head diameter is designed for use with freshly cut or reconditioned valve seats, restoring a correct sealing surface in worn, damaged, or previously machined cylinder heads
• Micro polished valve stems minimize oil retention and reduce drag against the valve guide, ensuring smooth, consistent motion across the full RPM range
• Swirl polished valve heads optimize intake charge airflow across the valve face, improving combustion efficiency and supporting peak power output in both GE and GTE builds
• Back-cut head design reduces overall valve mass, enabling higher RPM capability, greater boost pressure tolerance on the 2JZ-GTE, and compatibility with aggressive cam profiles without increasing valve spring seat pressures
• Maximized under-head dish removes additional mass while preserving full structural integrity under sustained high-temperature and high-pressure operating conditions
• Precision-adjusted valve tip lengths reduce tipping requirements during installation, maintaining correct valvetrain geometry and minimizing setup time when dialing in valve lash
• Engineered keeper groove geometry balances intake and exhaust spring pressures across the valvetrain, reducing reliance on valve spring shims and optimizing performance from GSC spring and retainer kits
• Valve tips hardened or stellite-tipped to within 5 Rockwell C of the rocker or tappet contact surface, minimizing tip wear over the full service life of the valve
• Designed, machined, and flow tested in-house on CNC machining centers using advanced 3D FEA and real-world flow simulation software validated in the specific 2JZ application

Specifications

• Position: Intake (set of 12 - complete engine set for inline-6)
• Valve Head Diameter: 34.50mm (+1mm oversized)
• Valve Stem Diameter: 6.0mm
• Overall Valve Length: 98.40mm
• Material: Modified 21-4N stainless steel
• Stem Finish: Micro polished
• Head Finish: Swirl polished with back cut; maximized under-head dish
• Application Engine: Toyota 2JZ-GE / 2JZ-GTE (3.0L DOHC I6, naturally aspirated and twin turbocharged)
• Quantity per Set: 12

Included Components

• 12x GSC Power Division +1mm Oversized 21-4N Intake Valves (34.50mm head, 6.0mm stem, 98.40mm length)

Product Description

The GSC Power Division 2064-12 is a complete set of twelve +1mm oversized (34.50mm) 21-4N stainless intake valves for the Toyota 2JZ-GE and 2JZ-GTE engines, covering the 1993-1998 Toyota Supra in both naturally aspirated and twin turbocharged form, as well as the 1993-2005 Lexus GS300, 1992-2000 Lexus SC300, and 2001-2005 Lexus IS300 and IS300 SportCross. The 2JZ is a 3.0L DOHC inline-6 with 12 intake valves total, and this set supplies the complete intake side for a full head rebuild on heads that have been machined for oversized seats. Built from a modified 21-4N stainless steel alloy, these valves deliver a meaningful performance and durability upgrade over stock components in both street-driven and high-output builds.

The +1mm oversized head is the defining characteristic of the 2064-12 and makes it the correct choice specifically when the cylinder head has been machined or reconditioned with oversized intake valve seats. This is common during professional head rebuilds where the original seat has suffered pitting, heat damage, or erosion that cannot be corrected by a standard valve grind - situations where a larger valve matched to a freshly cut seat is required to restore proper sealing geometry. All construction details carry over from GSC's proven stainless valve line: swirl polished and back-cut heads for improved flow and reduced mass, micro polished stems for reduced guide drag and oil retention, precision tip lengths for easier lash setup, and an engineered keeper groove geometry that minimizes spring shim requirements and correctly balances valvetrain spring pressures.

Sold as a complete set of 12, the GSC 2064-12 requires the cylinder head to have been machined for oversized (34.50mm) intake valve seats before installation - it is not interchangeable with stock 33.50mm seats without machine work. For heads with unmodified standard seats, refer to GSC part number 2062-12 (STD 33.50mm). For a complete high-performance valvetrain rebuild on a machined head, GSC recommends pairing the 2064-12 with the +1mm oversized exhaust valves (GSC2063-12), Manganese Bronze intake valve guides (GSC3032), and Viton valve stem seals (GSC1030). This valve is equally appropriate for high-power 2JZ-GTE builds as for naturally aspirated GE engine rebuilds requiring oversized valves due to prior head machine work.