In 2026, the part numbers 964246 3625 (Left) and 964247 3560 (Right) refer to high-performance, motorsport-grade camshafts specifically designed for the Porsche 911 (964) Turbo / GT2 racing engines. These are often categorized as “Sprint” or “GT2 Evolution” profiles, optimized for high-boost applications and top-end power.

1. Technical Specifications

These camshafts are a significant departure from the standard 964 or 930 Turbo profiles. They are designed for engines using mechanical lifters (solid rockers) rather than hydraulic ones.

• Application: Porsche 964 Turbo S, 3.6 Turbo, and 993 GT2 (Race versions).

• Profile Characteristics:

  • Increased Lift: Designed to maximize air intake under high boost pressures.

  • Duration: Optimized for a power band that peaks between 5,500 and 7,200 RPM.

  • Lobe Center: Specifically ground to reduce overlap, preventing “blow-through” where boost pressure escapes through the exhaust valve.

3. Compatibility & Requirements

If you are planning to install these 964 GT2 cams into a standard 911 engine, several modifications are mandatory:

• Mechanical Rockers: You cannot run these cams with hydraulic lifters. You must convert the heads to solid rockers (like those found on the 964 RS or 911 RSR).

• Valve Spring Upgrade: Due to the aggressive lift profile, factory valve springs may reach “coil bind” or suffer from valve float at high RPM. High-rate racing springs (e.g., Titanium retainers) are highly recommended.

• Piston-to-Valve Clearance: You must “clay” the engine during assembly. The increased duration and lift of the GT2 profile often require deeper valve pockets in the pistons.

4. Identification Guide

Authentic Porsche units will have the numbers stamped into the end of the shaft (distributor side or drive side).

• 964.105.246.03 (or similar variation) is the internal Porsche part number.

• 3625 / 3560 are often the specific grind or casting identifiers used by the manufacturer (likely Dr. Schrick or Atiwe) to denote the specific GT2 profile.

5. Installation & Timing

Setting the timing on GT2 camshafts is critical. Unlike a standard 964 where you align the dots, these require a dial indicator to set the “Lift at TDC” (Top Dead Center). For this specific profile, the intake lift at TDC is typically set significantly higher than a standard Turbo to account for the aggressive ramp rate.